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

int main() {
    int L = 1, R = (int)1e9;
    while (abs(L - R) > 1) {
        int mid = (L + R) / 2;
        cout << mid << endl;
        fflush(stdout);
        int re;
        cin >> re;
        if (re == 1) {
            R = mid;
        } else if (re == -1) {
            L = mid;
        } else {
            return 0;
        }
    }
    cout << L << endl;
    fflush(stdout);
    int re;
    cin >> re;
    if (re == -1)
        cout << ++L << endl;
    else
        return 0;
}