/* LittleFall : Hello! */
#include <bits/stdc++.h>
using namespace std;
inline int read() {
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9') {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9') {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x * f;
}
int query(int n) {
    printf("%d\n", n);
    fflush(stdout);
    return read();
}
int main(void) {
    int lef = 1, rig = 1000000000;
    while (lef <= rig) {
        int mid = (lef + rig) >> 1;
        int res = query(mid);
        if (res == 0)
            exit(0);
        else if (res == 1)
            rig = mid - 1;
        else
            lef = mid + 1;
    }

    return 0;
}