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