#include <iostream>
#include <stdio.h>
#include <string.h>

using namespace std;

int main() {
    int l = 1, r = 1e9, m, x;
    while (true) {
        m = (l + r) >> 1;
        printf("%d\n", m);
        fflush(stdout);
        scanf("%d", &x);
        if (x == 1) {
            r = m - 1;
        } else if (x == -1) {
            l = m + 1;
        } else {
            break;
        }
    }
}