#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
#define rep(a, b, c) for (int a = b; a < (int)c; ++a)

vector<int> xm = {-1, 1, 0, 0};
vector<int> ym = {0, 0, 1, -1};

const ll MOD = 998244353;

int main()
{
    int l = 0, r = 1000000000;
    while (l + 1 < r)
    {
        int mid = (l + r) / 2;
        cout << mid << endl;
        int res;
        cin >> res;
        if (res == 0)
        {
            r = mid;
        }
        else
        {
            l = mid;
        }
    }
    cout << l << endl;
}