#include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <utility>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
#include <stack>
#include <queue>
 
using namespace std;
 
#define pb(n)	push_back(n)
#define mp(n,m) make_pair(n,m)
#define fi 	first
#define se 	second
#define all(r) (r).begin(),(r).end()

#define rep(i,n) for(int i=0; i<(n); i++)
#define repc(i,a,b) for(int i=(a); i<(b); i++)

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
const int IMAX=((1<<30)-1)*2+1;
const double EPS=1e-10;
//int mod=1000000007


double f[7]={35.5,37.5,40.0,43.0,50.0,55.0,70.0};
double t[7]={71.0,77.0,83.0,89.0,105.0,116.0,148.0};
string s[8]={"AAA","AA","A","B","C","D","E","NA"};




int main(){
	double d,e;
	while(cin>>d>>e){
		rep(i,8){
			if(i==7||(d<f[i]&&e<t[i])){
				cout<<s[i]<<endl;
				break;
			}
		}
	}
}