#include <malloc.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

//ABC166D
//ABC166C
//ABC166B
//ABC166A
int main(void) {
  int n, k, i, cou=0, tmp;
  char a[3];
  scanf("%s", a);
  if(a[1]=='B') printf("ARC");
  else printf("ABC");

}
