include

using namespace std;

int main() {

char grade[6] = { 'E' , 'D' , 'C' , 'B' , 'A' , 'A'};

int score;
cin >> score;

score / 10 <= 5 ? cout << grade[0] << endl : cout << grade[(score / 10) - 5] << endl;

return 0;

}