#include<stdio.h>


int main()

{

int n;

scanf("%d",&n);

switch(n/10)

{case 10:case 9:printf("A");break;

case 8:printf("B");break;

 case 7:printf("C");break; case 6:printf("D");break;

 default :printf("E");

}

 

return 0;

}