#include<bits/stdc++.h>
#define int long long
using namespace std;
int l=1,r=1000000000;
signed main()
{
	while(l<r)
	{
		int mid=(l+r)>>1,x;
		cout<<mid<<endl;
		fflush(stdout);
		cin>>x;
		if(x==-1)l=mid+1;
		if(x==1)r=mid;
		if(!x)return 0;
	}
	return 0;
}