Submission #206341

# Submission time Handle Problem Language Result Execution time Memory
206341 2020-03-03T02:16:23 Z autumn_eel Detecting Molecules (IOI16_molecules) C++14
46 / 100
35 ms 25720 KB
#include <bits/stdc++.h>
#define rep(i,n)for(int i=0;i<(n);i++)
#include "molecules.h"
using namespace std;

bitset<10001>bit[10001];
std::vector<int> find_subset(int l, int u, std::vector<int> w) {
	bit[0][0]=1;
	rep(i,w.size()){
		bit[i+1]=bit[i]|(bit[i]<<w[i]);
	}
	for(int i=l;i<=u;i++){
		if(bit[w.size()][i]==1){
			int x=w.size(),y=i;
			vector<int>ans;
			while(x){
				x--;
				if(y>=w[x]&&bit[x][y-w[x]]){
					ans.push_back(x);
					y-=w[x];
				}
			}
			assert(y==0);
			reverse(ans.begin(),ans.end());
			return ans;
		}
	}
	return {};
}

Compilation message

molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:2:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i,n)for(int i=0;i<(n);i++)
                              ^
molecules.cpp:9:2: note: in expansion of macro 'rep'
  rep(i,w.size()){
  ^~~
# Verdict Execution time Memory Grader output
1 Correct 5 ms 256 KB OK (n = 1, answer = NO)
2 Correct 5 ms 256 KB OK (n = 1, answer = NO)
3 Correct 5 ms 256 KB OK (n = 1, answer = YES)
4 Correct 5 ms 256 KB OK (n = 2, answer = YES)
5 Correct 5 ms 256 KB OK (n = 2, answer = YES)
6 Correct 5 ms 376 KB OK (n = 3, answer = YES)
7 Correct 5 ms 376 KB OK (n = 3, answer = YES)
8 Correct 4 ms 376 KB OK (n = 3, answer = YES)
9 Correct 5 ms 376 KB OK (n = 3, answer = YES)
10 Correct 5 ms 376 KB OK (n = 3, answer = YES)
11 Correct 5 ms 376 KB OK (n = 3, answer = YES)
12 Correct 5 ms 376 KB OK (n = 3, answer = YES)
13 Correct 5 ms 376 KB OK (n = 3, answer = NO)
14 Correct 5 ms 256 KB OK (n = 3, answer = YES)
15 Correct 4 ms 256 KB OK (n = 3, answer = YES)
16 Correct 5 ms 256 KB OK (n = 3, answer = NO)
17 Correct 5 ms 376 KB OK (n = 3, answer = NO)
18 Correct 5 ms 504 KB OK (n = 100, answer = NO)
19 Correct 5 ms 380 KB OK (n = 100, answer = YES)
# Verdict Execution time Memory Grader output
1 Correct 5 ms 380 KB OK (n = 12, answer = YES)
2 Correct 5 ms 376 KB OK (n = 12, answer = YES)
3 Correct 5 ms 376 KB OK (n = 12, answer = NO)
4 Correct 5 ms 376 KB OK (n = 12, answer = NO)
5 Correct 4 ms 376 KB OK (n = 12, answer = YES)
6 Correct 5 ms 376 KB OK (n = 12, answer = YES)
7 Correct 5 ms 376 KB OK (n = 12, answer = YES)
8 Correct 5 ms 376 KB OK (n = 12, answer = YES)
9 Correct 5 ms 376 KB OK (n = 6, answer = YES)
10 Correct 5 ms 376 KB OK (n = 12, answer = YES)
11 Correct 5 ms 376 KB OK (n = 100, answer = NO)
12 Correct 5 ms 504 KB OK (n = 100, answer = YES)
13 Correct 5 ms 376 KB OK (n = 100, answer = NO)
14 Correct 5 ms 376 KB OK (n = 100, answer = YES)
15 Correct 5 ms 376 KB OK (n = 100, answer = YES)
16 Correct 5 ms 376 KB OK (n = 100, answer = YES)
17 Correct 5 ms 504 KB OK (n = 100, answer = YES)
# Verdict Execution time Memory Grader output
1 Correct 5 ms 256 KB OK (n = 1, answer = NO)
2 Correct 5 ms 256 KB OK (n = 1, answer = NO)
3 Correct 5 ms 256 KB OK (n = 1, answer = YES)
4 Correct 5 ms 256 KB OK (n = 2, answer = YES)
5 Correct 5 ms 256 KB OK (n = 2, answer = YES)
6 Correct 5 ms 376 KB OK (n = 3, answer = YES)
7 Correct 5 ms 376 KB OK (n = 3, answer = YES)
8 Correct 4 ms 376 KB OK (n = 3, answer = YES)
9 Correct 5 ms 376 KB OK (n = 3, answer = YES)
10 Correct 5 ms 376 KB OK (n = 3, answer = YES)
11 Correct 5 ms 376 KB OK (n = 3, answer = YES)
12 Correct 5 ms 376 KB OK (n = 3, answer = YES)
13 Correct 5 ms 376 KB OK (n = 3, answer = NO)
14 Correct 5 ms 256 KB OK (n = 3, answer = YES)
15 Correct 4 ms 256 KB OK (n = 3, answer = YES)
16 Correct 5 ms 256 KB OK (n = 3, answer = NO)
17 Correct 5 ms 376 KB OK (n = 3, answer = NO)
18 Correct 5 ms 504 KB OK (n = 100, answer = NO)
19 Correct 5 ms 380 KB OK (n = 100, answer = YES)
20 Correct 5 ms 380 KB OK (n = 12, answer = YES)
21 Correct 5 ms 376 KB OK (n = 12, answer = YES)
22 Correct 5 ms 376 KB OK (n = 12, answer = NO)
23 Correct 5 ms 376 KB OK (n = 12, answer = NO)
24 Correct 4 ms 376 KB OK (n = 12, answer = YES)
25 Correct 5 ms 376 KB OK (n = 12, answer = YES)
26 Correct 5 ms 376 KB OK (n = 12, answer = YES)
27 Correct 5 ms 376 KB OK (n = 12, answer = YES)
28 Correct 5 ms 376 KB OK (n = 6, answer = YES)
29 Correct 5 ms 376 KB OK (n = 12, answer = YES)
30 Correct 5 ms 376 KB OK (n = 100, answer = NO)
31 Correct 5 ms 504 KB OK (n = 100, answer = YES)
32 Correct 5 ms 376 KB OK (n = 100, answer = NO)
33 Correct 5 ms 376 KB OK (n = 100, answer = YES)
34 Correct 5 ms 376 KB OK (n = 100, answer = YES)
35 Correct 5 ms 376 KB OK (n = 100, answer = YES)
36 Correct 5 ms 504 KB OK (n = 100, answer = YES)
37 Correct 5 ms 376 KB OK (n = 28, answer = YES)
38 Correct 5 ms 376 KB OK (n = 27, answer = YES)
39 Correct 5 ms 376 KB OK (n = 90, answer = YES)
40 Correct 5 ms 504 KB OK (n = 100, answer = YES)
41 Correct 5 ms 504 KB OK (n = 100, answer = YES)
42 Correct 5 ms 376 KB OK (n = 10, answer = YES)
43 Correct 5 ms 376 KB OK (n = 100, answer = YES)
44 Correct 5 ms 376 KB OK (n = 100, answer = YES)
45 Correct 5 ms 376 KB OK (n = 100, answer = YES)
46 Correct 5 ms 376 KB OK (n = 100, answer = YES)
47 Correct 5 ms 376 KB OK (n = 100, answer = NO)
48 Correct 5 ms 504 KB OK (n = 100, answer = NO)
49 Correct 5 ms 376 KB OK (n = 100, answer = NO)
50 Correct 5 ms 376 KB OK (n = 100, answer = YES)
51 Correct 5 ms 376 KB OK (n = 100, answer = YES)
52 Correct 5 ms 504 KB OK (n = 100, answer = YES)
53 Correct 5 ms 376 KB OK (n = 100, answer = YES)
54 Correct 5 ms 376 KB OK (n = 100, answer = YES)
# Verdict Execution time Memory Grader output
1 Correct 5 ms 256 KB OK (n = 1, answer = NO)
2 Correct 5 ms 256 KB OK (n = 1, answer = NO)
3 Correct 5 ms 256 KB OK (n = 1, answer = YES)
4 Correct 5 ms 256 KB OK (n = 2, answer = YES)
5 Correct 5 ms 256 KB OK (n = 2, answer = YES)
6 Correct 5 ms 376 KB OK (n = 3, answer = YES)
7 Correct 5 ms 376 KB OK (n = 3, answer = YES)
8 Correct 4 ms 376 KB OK (n = 3, answer = YES)
9 Correct 5 ms 376 KB OK (n = 3, answer = YES)
10 Correct 5 ms 376 KB OK (n = 3, answer = YES)
11 Correct 5 ms 376 KB OK (n = 3, answer = YES)
12 Correct 5 ms 376 KB OK (n = 3, answer = YES)
13 Correct 5 ms 376 KB OK (n = 3, answer = NO)
14 Correct 5 ms 256 KB OK (n = 3, answer = YES)
15 Correct 4 ms 256 KB OK (n = 3, answer = YES)
16 Correct 5 ms 256 KB OK (n = 3, answer = NO)
17 Correct 5 ms 376 KB OK (n = 3, answer = NO)
18 Correct 5 ms 504 KB OK (n = 100, answer = NO)
19 Correct 5 ms 380 KB OK (n = 100, answer = YES)
20 Correct 5 ms 380 KB OK (n = 12, answer = YES)
21 Correct 5 ms 376 KB OK (n = 12, answer = YES)
22 Correct 5 ms 376 KB OK (n = 12, answer = NO)
23 Correct 5 ms 376 KB OK (n = 12, answer = NO)
24 Correct 4 ms 376 KB OK (n = 12, answer = YES)
25 Correct 5 ms 376 KB OK (n = 12, answer = YES)
26 Correct 5 ms 376 KB OK (n = 12, answer = YES)
27 Correct 5 ms 376 KB OK (n = 12, answer = YES)
28 Correct 5 ms 376 KB OK (n = 6, answer = YES)
29 Correct 5 ms 376 KB OK (n = 12, answer = YES)
30 Correct 5 ms 376 KB OK (n = 100, answer = NO)
31 Correct 5 ms 504 KB OK (n = 100, answer = YES)
32 Correct 5 ms 376 KB OK (n = 100, answer = NO)
33 Correct 5 ms 376 KB OK (n = 100, answer = YES)
34 Correct 5 ms 376 KB OK (n = 100, answer = YES)
35 Correct 5 ms 376 KB OK (n = 100, answer = YES)
36 Correct 5 ms 504 KB OK (n = 100, answer = YES)
37 Correct 5 ms 376 KB OK (n = 28, answer = YES)
38 Correct 5 ms 376 KB OK (n = 27, answer = YES)
39 Correct 5 ms 376 KB OK (n = 90, answer = YES)
40 Correct 5 ms 504 KB OK (n = 100, answer = YES)
41 Correct 5 ms 504 KB OK (n = 100, answer = YES)
42 Correct 5 ms 376 KB OK (n = 10, answer = YES)
43 Correct 5 ms 376 KB OK (n = 100, answer = YES)
44 Correct 5 ms 376 KB OK (n = 100, answer = YES)
45 Correct 5 ms 376 KB OK (n = 100, answer = YES)
46 Correct 5 ms 376 KB OK (n = 100, answer = YES)
47 Correct 5 ms 376 KB OK (n = 100, answer = NO)
48 Correct 5 ms 504 KB OK (n = 100, answer = NO)
49 Correct 5 ms 376 KB OK (n = 100, answer = NO)
50 Correct 5 ms 376 KB OK (n = 100, answer = YES)
51 Correct 5 ms 376 KB OK (n = 100, answer = YES)
52 Correct 5 ms 504 KB OK (n = 100, answer = YES)
53 Correct 5 ms 376 KB OK (n = 100, answer = YES)
54 Correct 5 ms 376 KB OK (n = 100, answer = YES)
55 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
56 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
57 Correct 19 ms 12792 KB OK (n = 10000, answer = YES)
58 Correct 20 ms 12792 KB OK (n = 10000, answer = YES)
59 Correct 17 ms 12664 KB OK (n = 10000, answer = YES)
60 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
61 Correct 18 ms 12792 KB OK (n = 10000, answer = NO)
62 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
63 Correct 17 ms 12664 KB OK (n = 10000, answer = NO)
64 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
65 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
66 Correct 18 ms 12668 KB OK (n = 10000, answer = YES)
67 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
68 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
69 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
70 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
71 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
72 Correct 6 ms 1400 KB OK (n = 865, answer = YES)
73 Correct 6 ms 1276 KB OK (n = 820, answer = YES)
# Verdict Execution time Memory Grader output
1 Correct 5 ms 256 KB OK (n = 1, answer = NO)
2 Correct 5 ms 256 KB OK (n = 1, answer = NO)
3 Correct 5 ms 256 KB OK (n = 1, answer = YES)
4 Correct 5 ms 256 KB OK (n = 2, answer = YES)
5 Correct 5 ms 256 KB OK (n = 2, answer = YES)
6 Correct 5 ms 376 KB OK (n = 3, answer = YES)
7 Correct 5 ms 376 KB OK (n = 3, answer = YES)
8 Correct 4 ms 376 KB OK (n = 3, answer = YES)
9 Correct 5 ms 376 KB OK (n = 3, answer = YES)
10 Correct 5 ms 376 KB OK (n = 3, answer = YES)
11 Correct 5 ms 376 KB OK (n = 3, answer = YES)
12 Correct 5 ms 376 KB OK (n = 3, answer = YES)
13 Correct 5 ms 376 KB OK (n = 3, answer = NO)
14 Correct 5 ms 256 KB OK (n = 3, answer = YES)
15 Correct 4 ms 256 KB OK (n = 3, answer = YES)
16 Correct 5 ms 256 KB OK (n = 3, answer = NO)
17 Correct 5 ms 376 KB OK (n = 3, answer = NO)
18 Correct 5 ms 504 KB OK (n = 100, answer = NO)
19 Correct 5 ms 380 KB OK (n = 100, answer = YES)
20 Correct 5 ms 380 KB OK (n = 12, answer = YES)
21 Correct 5 ms 376 KB OK (n = 12, answer = YES)
22 Correct 5 ms 376 KB OK (n = 12, answer = NO)
23 Correct 5 ms 376 KB OK (n = 12, answer = NO)
24 Correct 4 ms 376 KB OK (n = 12, answer = YES)
25 Correct 5 ms 376 KB OK (n = 12, answer = YES)
26 Correct 5 ms 376 KB OK (n = 12, answer = YES)
27 Correct 5 ms 376 KB OK (n = 12, answer = YES)
28 Correct 5 ms 376 KB OK (n = 6, answer = YES)
29 Correct 5 ms 376 KB OK (n = 12, answer = YES)
30 Correct 5 ms 376 KB OK (n = 100, answer = NO)
31 Correct 5 ms 504 KB OK (n = 100, answer = YES)
32 Correct 5 ms 376 KB OK (n = 100, answer = NO)
33 Correct 5 ms 376 KB OK (n = 100, answer = YES)
34 Correct 5 ms 376 KB OK (n = 100, answer = YES)
35 Correct 5 ms 376 KB OK (n = 100, answer = YES)
36 Correct 5 ms 504 KB OK (n = 100, answer = YES)
37 Correct 5 ms 376 KB OK (n = 28, answer = YES)
38 Correct 5 ms 376 KB OK (n = 27, answer = YES)
39 Correct 5 ms 376 KB OK (n = 90, answer = YES)
40 Correct 5 ms 504 KB OK (n = 100, answer = YES)
41 Correct 5 ms 504 KB OK (n = 100, answer = YES)
42 Correct 5 ms 376 KB OK (n = 10, answer = YES)
43 Correct 5 ms 376 KB OK (n = 100, answer = YES)
44 Correct 5 ms 376 KB OK (n = 100, answer = YES)
45 Correct 5 ms 376 KB OK (n = 100, answer = YES)
46 Correct 5 ms 376 KB OK (n = 100, answer = YES)
47 Correct 5 ms 376 KB OK (n = 100, answer = NO)
48 Correct 5 ms 504 KB OK (n = 100, answer = NO)
49 Correct 5 ms 376 KB OK (n = 100, answer = NO)
50 Correct 5 ms 376 KB OK (n = 100, answer = YES)
51 Correct 5 ms 376 KB OK (n = 100, answer = YES)
52 Correct 5 ms 504 KB OK (n = 100, answer = YES)
53 Correct 5 ms 376 KB OK (n = 100, answer = YES)
54 Correct 5 ms 376 KB OK (n = 100, answer = YES)
55 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
56 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
57 Correct 19 ms 12792 KB OK (n = 10000, answer = YES)
58 Correct 20 ms 12792 KB OK (n = 10000, answer = YES)
59 Correct 17 ms 12664 KB OK (n = 10000, answer = YES)
60 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
61 Correct 18 ms 12792 KB OK (n = 10000, answer = NO)
62 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
63 Correct 17 ms 12664 KB OK (n = 10000, answer = NO)
64 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
65 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
66 Correct 18 ms 12668 KB OK (n = 10000, answer = YES)
67 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
68 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
69 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
70 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
71 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
72 Correct 6 ms 1400 KB OK (n = 865, answer = YES)
73 Correct 6 ms 1276 KB OK (n = 820, answer = YES)
74 Correct 17 ms 9592 KB OK (n = 7500, answer = NO)
75 Runtime error 35 ms 25720 KB Execution killed with signal 11 (could be triggered by violating memory limits)
76 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 5 ms 256 KB OK (n = 1, answer = NO)
2 Correct 5 ms 256 KB OK (n = 1, answer = NO)
3 Correct 5 ms 256 KB OK (n = 1, answer = YES)
4 Correct 5 ms 256 KB OK (n = 2, answer = YES)
5 Correct 5 ms 256 KB OK (n = 2, answer = YES)
6 Correct 5 ms 376 KB OK (n = 3, answer = YES)
7 Correct 5 ms 376 KB OK (n = 3, answer = YES)
8 Correct 4 ms 376 KB OK (n = 3, answer = YES)
9 Correct 5 ms 376 KB OK (n = 3, answer = YES)
10 Correct 5 ms 376 KB OK (n = 3, answer = YES)
11 Correct 5 ms 376 KB OK (n = 3, answer = YES)
12 Correct 5 ms 376 KB OK (n = 3, answer = YES)
13 Correct 5 ms 376 KB OK (n = 3, answer = NO)
14 Correct 5 ms 256 KB OK (n = 3, answer = YES)
15 Correct 4 ms 256 KB OK (n = 3, answer = YES)
16 Correct 5 ms 256 KB OK (n = 3, answer = NO)
17 Correct 5 ms 376 KB OK (n = 3, answer = NO)
18 Correct 5 ms 504 KB OK (n = 100, answer = NO)
19 Correct 5 ms 380 KB OK (n = 100, answer = YES)
20 Correct 5 ms 380 KB OK (n = 12, answer = YES)
21 Correct 5 ms 376 KB OK (n = 12, answer = YES)
22 Correct 5 ms 376 KB OK (n = 12, answer = NO)
23 Correct 5 ms 376 KB OK (n = 12, answer = NO)
24 Correct 4 ms 376 KB OK (n = 12, answer = YES)
25 Correct 5 ms 376 KB OK (n = 12, answer = YES)
26 Correct 5 ms 376 KB OK (n = 12, answer = YES)
27 Correct 5 ms 376 KB OK (n = 12, answer = YES)
28 Correct 5 ms 376 KB OK (n = 6, answer = YES)
29 Correct 5 ms 376 KB OK (n = 12, answer = YES)
30 Correct 5 ms 376 KB OK (n = 100, answer = NO)
31 Correct 5 ms 504 KB OK (n = 100, answer = YES)
32 Correct 5 ms 376 KB OK (n = 100, answer = NO)
33 Correct 5 ms 376 KB OK (n = 100, answer = YES)
34 Correct 5 ms 376 KB OK (n = 100, answer = YES)
35 Correct 5 ms 376 KB OK (n = 100, answer = YES)
36 Correct 5 ms 504 KB OK (n = 100, answer = YES)
37 Correct 5 ms 376 KB OK (n = 28, answer = YES)
38 Correct 5 ms 376 KB OK (n = 27, answer = YES)
39 Correct 5 ms 376 KB OK (n = 90, answer = YES)
40 Correct 5 ms 504 KB OK (n = 100, answer = YES)
41 Correct 5 ms 504 KB OK (n = 100, answer = YES)
42 Correct 5 ms 376 KB OK (n = 10, answer = YES)
43 Correct 5 ms 376 KB OK (n = 100, answer = YES)
44 Correct 5 ms 376 KB OK (n = 100, answer = YES)
45 Correct 5 ms 376 KB OK (n = 100, answer = YES)
46 Correct 5 ms 376 KB OK (n = 100, answer = YES)
47 Correct 5 ms 376 KB OK (n = 100, answer = NO)
48 Correct 5 ms 504 KB OK (n = 100, answer = NO)
49 Correct 5 ms 376 KB OK (n = 100, answer = NO)
50 Correct 5 ms 376 KB OK (n = 100, answer = YES)
51 Correct 5 ms 376 KB OK (n = 100, answer = YES)
52 Correct 5 ms 504 KB OK (n = 100, answer = YES)
53 Correct 5 ms 376 KB OK (n = 100, answer = YES)
54 Correct 5 ms 376 KB OK (n = 100, answer = YES)
55 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
56 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
57 Correct 19 ms 12792 KB OK (n = 10000, answer = YES)
58 Correct 20 ms 12792 KB OK (n = 10000, answer = YES)
59 Correct 17 ms 12664 KB OK (n = 10000, answer = YES)
60 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
61 Correct 18 ms 12792 KB OK (n = 10000, answer = NO)
62 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
63 Correct 17 ms 12664 KB OK (n = 10000, answer = NO)
64 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
65 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
66 Correct 18 ms 12668 KB OK (n = 10000, answer = YES)
67 Correct 19 ms 12664 KB OK (n = 10000, answer = YES)
68 Correct 18 ms 12792 KB OK (n = 10000, answer = YES)
69 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
70 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
71 Correct 18 ms 12664 KB OK (n = 10000, answer = YES)
72 Correct 6 ms 1400 KB OK (n = 865, answer = YES)
73 Correct 6 ms 1276 KB OK (n = 820, answer = YES)
74 Correct 17 ms 9592 KB OK (n = 7500, answer = NO)
75 Runtime error 35 ms 25720 KB Execution killed with signal 11 (could be triggered by violating memory limits)
76 Halted 0 ms 0 KB -