/* LittleFall : Hello! */
#include <bits/stdc++.h>
using namespace std;

int query(int n) {
    cout << n << endl;
    int res;
    cin >> res;
    return res;
}
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;
}