#include<bits/stdc++.h>
using namespace std;
int main(){
	short a;
	int mid,r=1000000000,l=0;
	while(true) {
		mid=(r+l)/2;
		cout<<mid<<endl;
		cin>>a;
		if(a==0)
			return 0;
		else if(a==1)
			r=mid-1;
		else
			l=mid+1;
	}
	return 0;
}