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