#include<bits/stdc++.h> using namespace std; int main(){ double 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; }