
#include <iostream>
#include<string>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<vector>
using namespace std;
int main(){
    float t1,t2;
    while(cin>>t1>>t2){
        if(t1<35.50&&t2<71.00)cout<<"AAA"<<endl;
        else if(t1<37.50&&t2<77.00)cout<<"AA"<<endl;
        else if(t1<40.00&&t2<83.00)cout<<"A"<<endl;
        else if(t1<43.00&&t2<89.00)cout<<"B"<<endl;
        else if(t1<50.00&&t2<105.00)cout<<"C"<<endl;
        else if(t1<55.00&&t2<116.00)cout<<"D"<<endl;
        else if(t1<70.00&&t2<148.00)cout<<"E"<<endl;
        else cout<<"NA"<<endl;
    }
    return 0;
}