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