#include<stdio.h>
int main()
{
char a[3];
scanf("%s",a);
if(a[0]=='A')
{if(a[1]=='B')
  {if(a[2]=='C')
{printf("ARC\n");}}}
if(a[0]=='A')
{if(a[1]=='R')
  {if(a[2]=='C')
{printf("ABC\n");}}}
return 0;   
}