#include <iostream>
#include <stdio.h>
#include <utility>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;
int main()
{
    double t5,t10;
	string ans;
	while(cin>>t5>>t10){
		if(t5<35.50&&t10<71.00){
			ans="AAA";
		}else if(t5<37.50&&t10<77.00){
			ans="AA";
		}else if(t5<40.00&&t10<83.00){
			ans="A";
		}else if(t5<43.00&&t10<89.00){
			ans="B";
		}else if(t5<50.00&&t10<105.00){
			ans="C";
		}else if(t5<55.00&&t10<116.00){
			ans="D";
		}else if(t5<70.00&&t10<148.00){
			ans="E";
		}else{
			ans="NA";
		}
		cout<<ans<<endl;
	}
    return 0;
}