#include <iostream>
#include <algorithm>
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;
}