#include <bits/stdc++.h>
using namespace std;
#define int long long
int n;
int l = 1;
int r = 1000000000;
int mid;
signed main() {
    cout << ((l + r) >> 1) << endl;
    fflush(stdout);
    mid = (l + r) >> 1;
    while (cin >> n) {
        if (n == 1) {
            r = mid;
            mid = (l + r) >> 1;
            cout << mid << endl;
            fflush(stdout);
        }
        if (n == -1) {
            l = mid + 1;
            mid = (l + r) >> 1;
            cout << mid << endl;
            fflush(stdout);
        }
        if (n == 0)
            break;
    }
}