#include<iostream>
#include<string>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int main(void){

	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;

	}
	return 0;
}