#include<bits/stdc++.h> using namespace std; int main(){ int a; cin >> a; if(a >= 90){ cout << "A"; }else if(a >= 80 && a < 90){ cout << "B"; }else if(a >= 70 && a < 80){ cout << "C"; }else if(a >= 60 && a < 70){ cout << "D"; }else if(a < 60){ cout <<"E"; } return 0; }