#include <iostream>
using namespace std;
int main() {
    int l = 0, r = 1e9, mid, res;
    mid = (l + r) / 2;
    for (int i = 0; i < 100; i++) {
        cout << mid << endl;
        fflush(stdout);
        cin >> res;
        if (res == 0)
            break;
        if (res == -1) {
            l = mid + 1;
            mid = (l + r) / 2;
        }
        if (res == 1) {
            r = mid;
            mid = (l + r) / 2;
        }
    }
    return 0;
}