#include <iostream>
using namespace std;
int main()
{
	double a = 0;
	double b = 0;
	while (cin >> a, cin >> 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;
}