#include <iostream>
#include <algorithm>
#include <functional>
#include <vector>
#include <cstdio>
#include <string>
#include <cmath>
#include <cfloat>
#include <map>
#include <queue>
#include <stack>
using namespace std;
int main(){
	
	double a,b;
	
	while(cin>>a>>b){
		if(a<35.5&&b<71)
			cout<<"AAA"<<endl;
		else if(a<37.5&&b<77)
			cout<<"AA"<<endl;
		else if(a<40&&b<83)
			cout<<"A"<<endl;
		else if(a<43&&b<89)
			cout<<"B"<<endl;
		else if(a<50&&b<105)
			cout<<"C"<<endl;
		else if(a<55&&b<116)
			cout<<"D"<<endl;
		else if(a<70&&b<148)
			cout<<"E"<<endl;
		else
			cout<<"NA"<<endl;
	}
	
}