#include <stdio.h>
#include <iostream>

using namespace std;

int main() {
	double a,b;

	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;
}