#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int Max = 0;
int solve(int l, int r, int cnt, int pre = 0, int suf = 0){
if (cnt <= 0 or l >= r)
return -1;
if (l+1 == r){
vector<int> res = ask(l);
if (res[0]+res[1] == 0)
return l;
return -1;
}
for (int mid = (l+r)>>1; mid < r; mid++){
vector<int> res = ask(mid);
if (res[0]+res[1] == 0)
return mid;
if (res[0]+res[1] == Max){
int ret = solve(l,mid,res[0]-pre, pre, res[1]);
if (ret != -1)
return ret;
return solve(mid+1, r, res[1]-suf, res[0], suf);
}
}
for (int mid = ((l+r)>>1)-1; mid >= l; mid--){
vector<int> res = ask(mid);
if (res[0]+res[1] == 0)
return mid;
if (res[0]+res[1] == Max){
int ret = solve(l,mid,res[0]-pre, pre, res[1]);
if (ret != -1)
return ret;
return solve(mid+1, r, res[1]-suf, res[0], suf);
}
}
return -1;
}
int find_best(int n){
for (int i = 0; i < min(n,1000); i++){
vector<int> res = ask(i);
Max = max(Max, res[0]+res[1]);
}
return solve(0, n, Max);
}
