#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <deque>
#include <stack>
#include <cmath>
#include <math.h>
#include <array>
#include <random>
#include <bitset>
#include <climits>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define endl '\n'
#define mod 1000000007
#define INF 0x3f3f3f3f
#define int long long
template <class x>
using ordered_set = tree<x, null_type, less<x>, rb_tree_tag, tree_order_statistics_node_update>;
typedef pair<int, int> ipair;
static inline int read()
{
int x = 0;char ch = getchar();
while (ch < '0' || ch>'9') ch = getchar();
while (ch >= '0' && ch <= '9') x = (x << 3) + (x << 1) + (ch ^ 48), ch = getchar();
return x;
}
static inline void print(const int &x) {
if (x > 9) print(x / 10);
putchar('0' + x % 10);
}
int wi[2000005];
vector<int> adj[200005];
set<int> b;
bool f=1;
void dfs(int x, int p=-1, int bad=0)
{
if(b.find(x)!=b.end()&&bad)
{
f=0;
// cout << x << " " << bad << endl;
}
if(b.find(x)!=b.end()) bad=1;
for(auto i : adj[x])
{
if(i!=p) dfs(i, x, bad);
}
}
signed main()
{
cin.tie(0) -> sync_with_stdio(0);
int n, m;
cin >> n >> m;
int r=0;
for(int i = 1;i <= n;i++)
{
int x, w;
cin >> x >> w;
if(x==0) r = i;
else
{
adj[x].push_back(i);
adj[i].push_back(x);
}
wi[i]=w;
}
vector<int> s;
for(int i = 1;i <= n;i++) s.push_back(i);
int ans=0;
do
{
b.clear();
f=1;
for(int i = 0;i < m;i++) b.insert(s[i]);
dfs(r);
if(f)
{
int cnt=0;
for(int i = 0;i < m;i++) cnt += wi[s[i]];
ans=max(ans, cnt);
}
}while(next_permutation(s.begin(), s.end()));
cout << ans;
}
