#include <stdio.h>
const int MAX = 1e9;
unsigned long int a, b = MAX, c = 0;
int main() {
    int i, ans;
    for (i = 0; i < 100; i++) {
        a = (b + c) >> 1;
        printf("%lu\n", a);
        fflush(stdout);
        scanf("%d", &ans);
        if (ans == -1) {
            c = a + 1;
        } else if (ans == 1) {
            b = a;
        } else if (ans == 0)
            break;
    }
    return 0;
}