#include <stdio.h>
  
  char main(){
  char B = "ABC";
  char R = "ARC";
  char num[3];
    scanf("%s %s %s", &num[0], &num[1], &num[2]);
    
   if(num = B){
   printf("%d",R);
   }
    else{
   printf("%d",B);
    }
    return 0;
  }