#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;

string s[] = { "AAA", "AA", "A", "B", "C", "D", "E" };
double a, b, table[2][7] = { { 35.5, 37.5, 40, 43, 50, 55, 70 },
{ 71, 77, 83, 89, 105, 116, 148 } };

int main(){
	while (cin >> a >> b){
		for (int i = 0; i < 7; i++){
			if (a < table[0][i] && b < table[1][i]){
				cout << s[i] << endl;
				break;
			}
			if (i == 6)cout << "NA\n";
		}
	}
}