#ifdef LOCAL
#define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
#define ll long long
#define rep(i,n) for(ll i=0;i<(ll)n;i++)
#define all(v) v.begin(),v.end()
const ll INF = (ll)2e18;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll ok = 1;
    ll ng = (ll)1e9 + 1;
    ll remain = 30;

    while(ng-ok>1&&remain){
        ll m = (ng + ok) / 2;
        cout << m << endl;
        ll num;
        cin >> num;
        if(num==1){
            ok = m;
        }
        else{
            ng = m;
        }
        remain--;
    }
    cout << ok << endl;
}