/*====Corycle====*/
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int inf = 0x3f3f3f3f;

int main() {
    //	freopen("_.in","r",stdin);
    //	freopen("_.out","w",stdout);
    int l = 1, r = 1e9;
    while (l <= r) {
        int mid = (l + r) >> 1;
        cout << mid << endl;
        fflush(stdout);
        int x;
        cin >> x;
        if (x == 0)
            return 0;
        if (x == 1)
            r = mid - 1;
        if (x == -1)
            l = mid + 1;
    }
    return 0;
}