#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
  int a = 1000000000;
  while (a) {
    cout << a << endl;
    int r;
    cin >> r;
    if (r == -1) return 0;
    if (r == 1) return 0;
    a >>= 1;
  }
}