#include<iostream>
using namespace std;

int main()
{
int a,b;

cin>>a>>b;

if(0<=a+b&&a+b<=3)
{

	cout<<"YES";

}
    else{

	if(a+b>=4) {


	cout<<"NO";	

	}
	else
	{
		if(a+b<0) 
		cout<<"negative";
        return 0; 
	}	

}
}

a,b=map(int,input().split()) if a+b>=0 and a+b<=3: print("YES") if a+b>=4: print("NO") if a+b<0: print("negative")