#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
//#define TEST
#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair<int, int> ii;
const int len = 2e5+5;
ii arr[len];
int pos, n, sum;
/*vector<int> ask(int i) {
fprintf(fout, "A %d\n", i);
fflush(fout);
vector<int> result(2);
if (fscanf(fin, "%d %d", &result[0], &result[1]) != 2) {
cerr << "tester error" << endl;
cerr << "could not read query response" << endl;
exit(0);
}
if (result[0] < 0) {
exit(0);
}
return result;
}*/
#ifdef TEST
vector<int> ask(int i){
printf("ask %d\n", i), fflush(stdout);
int a, b;
scanf("%d %d", &a, &b);
vector<int> temp;
temp.pb(a), temp.pb(b);
return temp;
}
#endif
ii val(int i){
if (arr[i] != mp(-1, -1))
return arr[i];
vector<int> temp = ask(i);
return arr[i] = mp(temp[0], temp[1]);
}
int bs(){
int l = pos, r = n-1, ans;
while (l <= r){
int mid = (l+r)/2;
if (val(mid) == val(pos)){
ans = mid;
l = mid+1;
}
else
r = mid-1;
}
return ans;
}
int find_best(int N){
n = N, sum = 0, pos = 0;
for (int i = 0; i < n; i++)
arr[i] = mp(-1, -1);
for (int i = 0; i < min(481, n); i++)
sum = max(sum, val(i).fi + val(i).se);
while (pos < n){
if (val(pos).fi+val(pos).se != sum){
if (val(pos) == mp(0, 0))
return pos;
pos++;
}
else{
pos = bs() + 1;
}
}
return 0;
}
#ifdef TEST
int main(int argc, char **argv) {
int n;
scanf("%d", &n);
printf("%d\n", find_best(n));
return 0;
}
#endif
