#include<bits/stdc++.h>
using namespace std;
#define int long long
#define FO(i,a,b) for(int i=a;i<=b;i++)
int k,l=1,r=1e9,mid; 
signed main(){
	while(l<r){
		mid=(l+r)/2;
		cout<<mid<<endl;
		cin>>k;
		if(k==0)return 0;
		else if(k==-1)l=mid+1;
		else r=mid-1;
	}
	return 0;
}