  #include<stdio.h>
#include<string.h>
    int main()
{
    char S,ABC,ARC;
    scanf("%c",&S);
    if(strcmp(S,ABC)==0);
      {printf("ARC");}
      
    if(strcmp(S,ARC)==0);
      {   printf("ABC");}
    
    
    
    
    
       
            
    

    
    
      
            
        
    
    
    
    
}
