#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;

ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;
    return gcd(b, a % b);
}
int lcm(int a, int b) {
    return a * b / gcd(a, b);
}




int main()
{

    int Q;
    Q = 1;
    //cin >> Q;



    while (Q--) {
       
        int m = 30;
        ll ans = 0;
        ll a = 0, b = 1e9;
        ll x = a + b; x /= 2;
        while (m) {
            m--;
            x= a + b; x /= 2;
            cout << x<<endl;
            ll t;
            cin >> t;
            if (t) {
                a = x+1;
                ans = x;
                
            }
            else {
                b = x;
                
            }
        }
        cout << ans;
    }
        return 0;
}