#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<n;i++)
ll po(ll root,ll p) {
    ll q=1;
    rep(i,p) {
        q*=root;
    }
    return q;
}

int main() {
    ll lef=1,rig=po(10,9);
    rep(i,30) {
        cout<<(lef+rig)/2<<endl;
        cout<<flush;
        ll mid=(lef+rig)/2;
        ll r;
        cin>>r;
        if(r==1) {
            return 0;
        }
        if(r==0) {
            rig=mid;
        }
        if(r==-1) {
            return 0;
        }
    }
}