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