#include<iostream> using namespace std; int main() {int S; cin>>S; if(90<=S&&S<=100) cout<<"A"; if(80<=S&&S<90) cout<<"B"; if(70<=S&&S<80) cout<<"C"; if(60<=S&&S<70) cout<<"D"; if(0<=S&&S<60) cout<<"E"; if(S<0) cout<<"EORR"; if(S>100) cout<<"EORR"; return 0; }