#include<iostream>
using namespace std;
string s[8]={"AAA","AA","A","B","C","D","E","NA"};
double a[8]={35.5 , 37.5 , 40.0 , 43.0, 50.0, 55.0, 70.0,9999999.9999999};
double b[8]={71.0 , 77.0 , 83.0 , 89.0,105.0,116.0,148.0,9999999.9999999};
double q,w;
int main(){
  while(cin>>q>>w){
    for(int i=0;i<8;i++){
      if(q<a[i]&&w<b[i]){
	cout<<s[i]<<endl;
	break;
}}}}