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