#include <bits/stdc++.h>
using namespace std;
vector<int> ask(int i);
vector <int> pos;
int find_best(int n){
//let us denote the number of item of u as f(u)
//from simple algebra we know that f(v-1)<500
//and since 17<log2(200000)<18 we know we need 18 operation
//for each query -- hence we can find every item of value
//higher than v at 18*500 = 9000 queries
int mx = 0;
for (int ind = 0; ind < 500; ind++){
vector <int> v = ask(ind);
if (v[0]+v[1]==0){return ind;}
mx=max(mx,v[0]+v[1]);
}
while (true){
int l=0;
int r=n-1;
while (l<r){
int m = (l+r)/2;
vector <int> v = ask(m);
if (v[0]+v[1]==0){return m;}
if (v[0]+v[1]<mx){
auto it = lower_bound(pos.begin(), pos.end(), m);
pos.insert(it, m);
r=m;
continue;
}
int lower=lower_bound(pos.begin(), pos.end(), m ) - pos.begin();
v[0]-=lower;
if (v[0]){r=m;}
else{l=m+1;}
}
if (l==r){
//justincase
if (binary_search(pos.begin(), pos.end(), l)){continue;}
else{
auto it = lower_bound(pos.begin(), pos.end(), l);
pos.insert(it, l);
}
}
}
return -1;
}
