#include <iostream>
#include <cstdio>
using namespace std;
int main() {
    int n, l, r, m;
    l = 1;
    r = 1e9;
    m = (1 + r) >> 1;
    while (1) {
        cout << m << endl;
        fflush(stdout);
        cin >> n;
        if (n == 0)
            return 0;
        if (n == -1) {
            l = m;
            m = (l + r) >> 1;
            if (r - l <= 1)
                m += 1;
        }
        if (n == 1) {
            r = m;
            m = (l + r) >> 1;
        }
    }
    return 0;
}