#include <cstdio>
#include <algorithm>
#include <string>
using namespace std;

int main() {
  for(float s, g;scanf(" %f %f", &s, &g) != EOF;) {
    string out;
    if(s < 35.50 && g < 71.00) out = "AAA";
    else if(s < 37.0 && g < 77.00) out = "AA";
    else if(s < 40.0 && g < 83.00) out = "A";
    else if(s < 43.0 && g < 89.00) out = "B";
    else if(s < 50.0 && g < 105.00) out = "C";
    else if(s < 55.0 && g < 116.00) out = "D";
    else if(s < 70.0 && g < 148.00) out = "E";
    else out = "NA";
    printf("%s\n", out.c_str());
  }
  return 0;
}