include<bits/stdc++.h>

using namespace std ; int main(){

int grade ;
cin >> grade ;
switch (grade)
{
case 5 :cout << "A" << endl; break ;
case 4 :cout << "B" << endl; break ;
case 3 :cout << "C" << endl; break ;
case 2 :cout << "D" << endl; break ;
case 1 :cout << "E" << endl;
}
return 0;

}