#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; }