#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector <int>;
using pii = pair <int, int>;
#define pb push_back
#define mp make_pairdefine F first
#define S second
#define N 200005
int mx;
int gg(int l, int r){
vi tmp, tmp1;
if (l == r) {
tmp = ask(l);
if (tmp[0] + tmp[1] == 0) return l;
return -1;
}
while (l <= r){
tmp = ask(l);
if (tmp[0] + tmp[1] == 0) return l;
if (tmp[0] + tmp[1] == mx) break;
l++;
}
while(l <= r){
tmp1 = ask(r);
if (tmp1[0] + tmp1[1] == 0) return r;
if (tmp1[0] + tmp1[1] == mx) break;
r--;
}
if (l > r) return -1;
if (tmp1[0] == tmp[0]) return -1;
if (l == r) return gg(l, r);
int mid = (l + r) / 2;
return max(gg(l, mid), gg(mid + 1, r));
}
int find_best(int n) {
for (int i = 0;i < 1000;i++){
vi ans = ask(i);
if (!(ans[0] + ans[1])) return i;
mx = max(mx, ans[0] + ans[1]);
}
return gg(0, n - 1);
}
