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

int main(void){
	int x,i;

	//scanf("%lf",&m);
	
	x = getchar();
	x=getchar();
	
	if(x=='B')
		printf("ARC\n");
	else
		printf("ABC\n");
	
	
	return 0;
}