#include "prize.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cassert>
#include <random>
using namespace std;
#define rep(i,n)for (int i=0; i<(n); i++)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define _1 first
#define _2 second
#define INF 1145141919
#define ret(x) {int cache=(x);if(cache!=-1)return cache;}
typedef pair<int, int> P;
mt19937 mt_rand(114514);
int mp = 0;
int solve(int l, int r, int num, int left) {
if (num == 0) return -1;
int mid = (l+r)/2;
for (; mid>=l; mid--) {
vector<int> ret = ask(mid);
if (ret[0]+ret[1] == 0) return mid;
if (ret[0]+ret[1] != mp) continue;
if (mid > l) {
ret(solve(l, mid-1, ret[0]-left, left));
}
if (mid < r) {
ret(solve(mid+1, r, num-ret[0], left+ret[0]));
}
}
return -1;
}
int find_best(int N) {
rep(i, 30) {
vector<int> ret = ask(mt_rand()%N);
mp = max(mp, ret[0]+ret[1]);
}
assert(mp < 500);
return solve(0, N-1, mp, 0);
}
