#include <iostream>

using namespace std;

int main()
{
	double t,ti;

	while(cin >> t >> ti){

	if(t < 35.50 && ti < 71.00)
	{
		cout << "AAA" << endl;
	}
	else if(t < 37.50 && ti < 77.00)
	{
		cout << "AA" << endl;
	}
	else if(t < 40.00 && ti < 83.00)
	{
		cout << "A" << endl;
	}
	else if(t < 43.00 && ti < 89.00)
	{
		cout << "B" << endl;
	}
	else if(t < 50.00 && ti < 105.00)
	{
		cout << "C" << endl;
	}
	else if(t < 55.00 && ti < 116.00)
	{
		cout << "D" << endl;
	}
	else if(t < 70 && ti < 148.00)
	{
		cout << "E" << endl;
	}

	else
		cout << "NA" << endl;
	}

	return 0;
}