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

int back;
int main() {
    int max = 1e9, min = 1;

    while (min <= max) {
        int mid = (min + max) / 2;
        cout << mid << endl;
        fflush(stdout);
        cin >> back;
        if (back == 0) {
            return 0;
        }
        if (back == -1) {
            min = mid + 1;
        }
        if (back == 1) {
            max = mid - 1;
        }
    }

    return 0;
}