#include <iostream>
using namespace std;
int main(void){
   // Your code here!
   double a, b;
   
   while(cin>>a>>b){
       if(a<35.50 && b<71.00){
           cout<<"AAA"<<endl;
       }
       else if(a<37.50 && b<77.00){
           cout<<"AA"<<endl;
       }
       else if(a<40.00 && b<83.00){
           cout<<"A"<<endl;
       }
       else if(a<43.00 && b<89.00){
           cout<<"B"<<endl;
       }
       else if(a<50.00 && b<105.00){
           cout<<"C"<<endl;
       }
       else if(a<55.00 && b<116.00){
           cout<<"D"<<endl;
       }
       else if(a<70.00 && b<148.00){
           cout<<"E"<<endl;
       }
       else  cout<<"NA"<<endl;
   }
   return 0;

}

