#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main() {
    double a, b;
    while (cin >> a >> b) {
        if (a < 35.5 && b < 71) {
            cout << "AAA" << endl;
        } else if (a < 37.5 && b < 77) {
            cout << "AA" << endl;
        } else if (a < 40 && b < 83) {
            cout << "A" << endl;
        } else if (a < 43 && b < 89) {
            cout << "B" << endl;
        } else if (a < 50 && b < 105) {
            cout << "C" << endl;
        } else if (a < 55 && b < 116) {
            cout << "D" << endl;
        } else if (a < 70 && b < 148) {
            cout << "E" << endl;
        } else {
            cout << "NA" << endl;
        }
    }
    return 0;
}