#include <bits/stdc++.h>
using namespace std;
vector <bool> is_small;
int sum;
vector <int> val;
int sol = -1;
vector <int> ask(int i);
void binary_search(int m, int s, int e, int left, int right){
if (sol != -1)return;
vector <int> a = ask(m);
if (a[0]+a[1] == 0)sol = m;
//if (a[0]+a[1] < sum){is_small[m] = 1; return;}
if (e-s <= 1)return;
if (a[0]-left > 0)binary_search((s+m)/2, s, m, left, a[1]);
if (a[1]-right > 0)binary_search((m+1+e)/2, m+1, e, a[0], right);
}
int find_best(int n){
if (n == 1)return 0;
is_small.resize(n, 0);
val.resize(n);
sum = 0;
for (int i = 0; i <= min(400, n-1); i++){
vector <int> a = ask(i);
val[i] = a[0]+a[1];
sum = max(sum, val[i]);
}
int start = -1;
for (int i = 0; i < min(401, n); i++){
//if (val[i] < sum)is_small[i] = 1;
if (val[i] >= sum)start = i;
if (val[i] == 0)return i;
}
binary_search(start, 0, n, 0, 0);
return sol;
}
