#include<iostream>
#include<cstdlib>
#include<cstdio>
using namespace std;
int main()
{
	int ll=1,rr=1000000000,opt;
	while(ll<=rr)
	{
		int mid=(ll+rr)/2;
		printf("%d\n",mid);
		fflush(stdout);
		scanf("%d",&opt);
		if(opt==1)return 0;
		else if(opt==-1)ll=mid+1;
		else rr=mid-1;
	}
	return 0;
}