#include <bits/stdc++.h>
using namespace std;
int main() {
  int m; cin >> m;
  int l = 1, r = 1000000001;
  while (l + 1 < r) {
    int mid = (l+r)/2;
    cout << mid << endl;
    int x; cin >> x;
    if (x == 1) {
      l = mid;
    }
    else r = mid;
  }
  cout << l << endl;
}