#include<bits/stdc++.h>
using namespace std;

#define pb push_back
#define fr first
#define sc second
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef pair<int,pii> pip; 
const int INF = (1<<25);
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

int main(){

  double a ,b;
  while(scanf("%lf %lf",&a,&b) != EOF){
    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;
  }
}