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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int ok = 0, ng = 1 << 30;
    while(ok + 1 < ng){
        int mid = (ok + ng) / 2;
        int res;
        cout << mid << endl;
        cin >> res;
        (res == 1 ? ok : ng) = mid;
    }
    cout << ok << endl;
}