#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
	int a,b;
	cin >> a >> b;
	if (a+b>=4)
	{
		cout<<"NO";
	}
	else if(a+b<0)
	{
		cout<<"negative";

	}
	else
	{
		cout<<"YES";
	}
	

}