#include <iostream>
#include <cstdio>
#include <string>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <iomanip>
#include <vector>

using namespace std;


double a, b;


int main()
{
	while (cin >> a >> b)
	{
		if (a<35.5 && b<71.0)
		{
			cout << "AAA" << endl;
		} else if (a<37.5 && b<77.0) {
			cout << "AA" << endl;
		} else if (a<40.0 && b<83.0) {
			cout << "A" << endl;
		} else if (a<43.0 && b<89.0) {
			cout << "B" << endl;
		} else if (a<50.0 && b<105.0) {
			cout << "C" << endl;
		} else if (a<55.0 && b<116.0) {
			cout << "D" << endl;
		} else if (a<70.0 && b<148.0) {
			cout << "E" << endl;
		} else {
			cout << "NA" << endl;
		}
	}
	
	return 0;
}