#include <bits/stdc++.h>
using namespace std;
int main()
{
    int l = 0, r = 1000000000;
    int md;
    while (r - l > 1)
    {
        md = (l + r) / 2;
        cout << md << endl;
        int tmp;
        cin >> tmp;
        if (abs(tmp) == 1)
            return 0;
        else
            r = md;
    }
}