#include<stdio.h>
int main(void)
{
	double a,b;

		while(scanf("%lf %lf",&a,&b)!=EOF) {
			if(35.50>a && 71.00>b){
				printf("AAA\n");
			}
			else if (37.50>a && 77.00>b){
				printf("AA\n");
			}
			else if (40.00>a && 83.00>b){
				printf("A\n");
			}
			else if (43.00>a && 89.00>b){
				printf("B\n");
			}
			else if(50.00>a && 95.00>b){
				printf("C\n");
			}
			else if(55.00>a && 122.00>b){
				printf("D\n");
			}
			else if(70.00>a && 148.00>b){
				printf("E\n");
			}
			else{
				printf("NA\n");
			}
		}
		return 0;
}