#include <bits/stdc++.h>

int main()
{
    long long ok = 0, ng = 1e9 + 3;
    int m = 30;
    while (m-- && ok < ng - 1) {
        long long mid = (ok + ng) / 2;
        std::cout << mid << std::endl;
        int r;
        std::cin >> r;
        if (r == 1) return 0;
        else if (r == 0) ng = mid;
        else return 0;
    }
}