#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<string>
#include<algorithm>
#include<utility>
#include<set>
#include<queue>

using namespace std;

typedef pair<int,int> PII;
typedef long long ll;

const double EPS = 1e-9;
int main(){

	string rank[8] = {"AAA","AA","A","B","C","D","E","NA"};
	double time500[8] = {35.50,37.50,40.00,43.00,50.00,55.00,70.00,0};
	double time1000[8] = {71.00,77.00,83.00,89.00,105.00,116.00,148.00,0};

	double n,m;
	while(cin>>n>>m){
		
		int r,rr;
		for(r=0;r<7;r++){
			if(n-time500[r] < -EPS)break;
		}
		for(rr = 0;rr<7;rr++){
			if(n-time1000[rr] < -EPS)break;
		}

		cout<<rank[max(r,rr)]<<endl;

	}

	return 0;
}