#include<iostream>
using namespace std;
int main(){
	float a,b;
	while(cin>>a>>b){
		if(a<35.5&&b<71.0){
			cout<<"AAA"<<endl;
		}
		else if(a<37.5&&b<77.0){
			cout<<"AA"<<endl;
		}
		else if(a<40.0&&b<83.0){
			cout<<'A'<<endl;
		}
		else if(a<43.0&&b<89.0){
			cout<<'B'<<endl;
		}
		else if(a<50.0&&b<105.0){
			cout<<'C'<<endl;
		}
		else if(a<55.0&&b<116.0){
			cout<<'D'<<endl;
		}
		else if(a<70.0&&b<148.0){
			cout<<'E'<<endl;
		}
		else{
			cout<<"NA"<<endl;
		}
	}
	return 0;
}