#include <bits/stdc++.h>
using namespace std;
int l = 1, r = 1000000000;
int main() {
    // freopen("a.txt","r",stdin);
    // freopen("b.txt","w",stdout);
    while (1) {
        int k;
        int mid = (l + r) / 2;
        printf("%d\n", mid);
        fflush(stdout);
        scanf("%d", &k);
        if (k == 0)
            return 0;
        else if (k == 1)
            r = mid - 1;
        else if (k == -1)
            l = mid + 1;
    }
    return 0;
}