#include<bits/stdc++.h>
using namespace std;
#include "prize.h"
//#include "grader.cpp"
int res=-1;
vector<vector<int>>v;
map<vector<int>,set<int>>mp;
void divide(int l,int r){
if(l>r||res!=-1)return;
if(l==r){
v[l]=ask(l);
mp[v[l]].insert(l);
if(v[l][0]+v[l][1]==0)res=l;
return;
}
int md=(l+r)>>1;
if(v[md].size()==0)v[md]=ask(md);
if(v[md][0]+v[md][1]==0)res=md;
mp[v[md]].insert(md);
if(!(mp[v[md]].size()&&*(mp[v[md]].begin())<md)&&v[md][0])divide(l,md-1);
if(!(mp[v[md]].size()&&*(mp[v[md]].rbegin())>md)&&v[md][1])divide(md+1,r);
}
int find_best(int n){
v.clear();
v.resize(n);
mp.clear();
res=-1;
v[0]=ask(0);
v[n-1]=ask(n-1);
mp[v[0]].insert(0);
mp[v[n-1]].insert(n-1);
if(v[0][0]+v[0][1]==0)return 0;
if(v[n-1][0]+v[n-1][1]==0)return n-1;
divide(1,n-2);
return res;
}
