#include <bits/stdc++.h>
using namespace std;
int main() {
    int l = 1, r = 1e9, mid, k;
    while (l <= r) {
        mid = (l + r) / 2;
        printf("%d\n", mid);
        fflush(stdout);
        scanf("%d", &k);
        if (k == 1)
            r = mid - 1;
        else if (k == -1)
            l = mid + 1;
        else
            return 0;
    }
    return 0;
}