#include <bits/stdc++.h>
using namespace std;

int main() {
    double a, b;
    while (cin >> a >> b) {
        if (a < 35.50 && b < 71.00) cout << "AAA" << endl;
        else if (a < 37.50 && b < 77.00) cout << "AA" << endl;
        else if (a < 40.00 && b < 83.00) cout << "A" << endl;
        else if (a < 43.00 && b < 89.00) cout << "B" << endl;
        else if (a < 50.00 && b < 105.00) cout << "C" << endl;
        else if (a < 55.00 && b < 116.00) cout << "D" << endl;
        else if (a < 70.00 && b < 148.00) cout << "E" << endl;
        else cout << "NA" << endl;
    }

    return 0;
}