#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
vector<int> memoiz[200005];
vector<int> customAsk(int x){
// Memoized version of ask
if(memoiz[x].empty()) return memoiz[x] = ask(x);
else return memoiz[x];
}
int key;
int solve(int l, int r, int offsL = 0, int offsR = 0){
if(l > r) return -1;
if(l == r) return customAsk(l)[0] + customAsk(l)[1] == 0 ? l : -1;
int m = (l+r)/2;
vector<int> res = customAsk(m);
while(res[0] + res[1] <= key){
if(res[0] + res[1] == 0) return m;
if(m == r) break;
m++;
res = customAsk(m);
}
if(m == r){
m = (l+r)/2;
while(res[0] + res[1] <= key){
if(res[0] + res[1] == 0) return m;
if(m == l) return -1;
m--;
res = customAsk(m);
}
}
int left = -1;
if(res[0] - offsL > 0) left = solve(l, m-1, offsL, res[1]);
if(left != -1) return left;
if(res[1] - offsR > 0) return solve(m+1, r, res[0], offsR);
return -1;
}
int find_best(int n) {
if(n < 5000){
for(int i = 0; i < n; i++) {
vector<int> res = customAsk(i);
if(res[0] + res[1] == 0)
return i;
}
}
key = sqrt(n);
int ans = solve(0, n-1);
for(int i = 0; i < n; i++) memoiz[i].clear();
return ans;
}
