#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 2e5+50;
int ans,n;
map<int,vector<int>> mp[maxn];
void solve(int l,int r){
if(l > r || ans != -1)return;
int md = (l+r)/2;
vector<int> res = ask(md);
if(res[0] + res[1] == 0){
ans = md;
return;
}
int sum = res[0] + res[1];
auto it = mp[sum].upper_bound(md);
if(it != mp[sum].end()){
if((*it).second[0] != res[0])
solve(md+1,r);
}
if(it != mp[sum].begin()){
it--;
if(it != mp[sum].begin() && it->second[1] != res[1])
solve(l,md-1);
}
mp[sum][md] = res;
}
int find_best(int N) {
n = N;
ans = -1;
solve(0,n-1);
return ans;
}
