#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
#define X first
#define Y second
using ii = pair<int, int>;
int n;
vector<int> V[200007];
ii ans(int i) {
if(V[i].size() == 0)
V[i] = ask(i);
return {V[i][0], V[i][1]};
}
int sum(int i) {
return ans(i).X + ans(i).Y;
}
int worst_sum;
int find_in_segment(int a, int b, int ok) {
if(!ok)
return -1;
int mid1 = (a + b) / 2;
if(sum(mid1) > sum(a - 1)) {
while(sum(a) < sum(mid1)) {
if(sum(a) == 0)
return a;
a++;
}
while(sum(b) < sum(mid1)) {
if(sum(b) == 0)
return b;
b--;
}
if(a < mid1) {
int x = find_in_segment(a + 1, mid1 - 1, ans(mid1).X - ans(a).X);
if(x != -1)
return x;
}
if(mid1 < b) {
int x = find_in_segment(mid1 + 1, b - 1, ans(b).X - ans(mid1).X);
if(x != -1)
return x;
}
return -1;
}
int mid2 = (a + b) / 2;
while(ans(mid1).X + ans(mid1).Y != sum(a - 1) && mid1 >= a) {
if(ans(mid1).X + ans(mid1).Y == 0)
return mid1;
mid1--;
}
if(mid1 > a) {
int x = find_in_segment(a, mid1 - 1, ans(mid1).X - ans(a - 1).X);
if(x != -1)
return x;
}
while(ans(mid2).X + ans(mid2).Y != sum(a - 1) && mid2 <= b) {
if(ans(mid2).X + ans(mid2).Y == 0)
return mid2;
mid2++;
}
if(mid2 < b) {
int x = find_in_segment(mid2 + 1, b, ans(b + 1).X - ans(mid2).X);
if(x != -1)
return x;
}
return -1;
}
int find_best(int n) {
::n = n;
int total = ans(0).Y;
V[n] = {total, 0};
if(total == 0)
return 0;
return find_in_segment(1, n - 1, total);
}
