#include<iostream>
using namespace std;

int main(){
while(1){
double a,b;
cin>>a;
if (cin.fail()) break;
cin>>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;}

}
}