#include<iostream> using namespace std; int main(){ int a,b; cin>>a; b=a/10; switch(b){ case 9: cout<<"A"<<endl; break; case 10: cout<<"A"<<endl; break; case 8: cout<<"B"<<endl; break; case 7: cout<<"C"<<endl; break; case 6: cout<<"D"<<endl; break; default: cout<<"E"<<endl; } return 0; }