#include <iostream>
using namespace std;
double a,b,t[8]={35.5,37.5,40.0,43.0,50.0,55.0,70.0,2e+9},u[8]={71.0,77.0,83.0,89.0,105.0,116.0,148.0,2e+9};
string s[8]={"AAA","AA","A","B","C","D","E","NA"};
int main(){
while(cin>>a>>b){
for(int i=0;i<8;i++){
if(a<t[i]&&b<u[i]){cout<<s[i]<<endl;break;}
}
}
}