#include <iostream>
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;
}