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

const int x_dir[] = {0, 1, 0, -1};
const int y_dir[] = {-1, 0, 1, 0};

int main()
{
    ll n = 1e9;
    for (int i=0; i<30; ++i) {
        ll x = n/2;
        cout << x << endl;
        int r;
        cin >> r;
        switch(r) {
            case 0:
                n = x;
                break;
            case 1:
            case -1:
                return 0;
        }        
    }
    return 0;
}