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

int main(){
    int m = 30;

    int h = 0,t = 1000000001;
    for(int i=0;i<m;i++){
        int c = (h+t) / 2 + 1;
        cout << c << endl;

        int che;
        cin >> che;

        if(che == 0) t = c-1;
        else h = c;

        if(t == h) break;
    }

    cout << h << endl;
}