#include 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; 
}	

} }