#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
int num = 0;
#define sz(a) (int)(a.size());
vector<int>res[200000];
int cnt = 0;
int solve(int l,int r,int lf = 0,int rg = 0){
if(l > r)return -1;
int mid = (l+r)/2;
for(int i=0;i<=r-l;i++){
int ml = mid-i/2;
int mr = mid+(i+1)/2;
int m = i%2==0?ml : mr;
int tmpl = i%2==0?0:mr-ml;
int tmpr = i%2==1?0:mr-ml;
res[m] = ask(m);
if(!res[m][0] && !res[m][1])return m;
if(res[m][0] + res[m][1] == num){
int c = -1;
if(res[m][0]-tmpl>lf)c = max(c,solve(l,ml-1,lf,res[m][1]+tmpl));
if(res[m][1]-tmpr>rg)c = max(c,solve(mr+1,r,res[m][0]+tmpr,rg));
return c;
}
}
return -1;
}
int find_best(int n) {
vector<int>a(n);
for(int i=0;i<n;i++)a[i] = i;
int p = 0;
for(int i=0;i<min(n,(int)(sqrt(n)+30));i++){
vector<int>res = ask(i);
if(!res[0] && !res[1])return i;
if(res[0] + res[1] > num){
num = res[0] + res[1];
p = i;
}
}
//d&c to try all small guys since < #small guys < sqrt(n)
return solve(p,n-1,p,0);
}
