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

int main(void)
{
    char name[4];
    gets(name);

    char name2[4] = "ABC";
    if((strcmp(name2,name)) == 0)
        printf("ARC\n");
    else
        printf("ABC\n");

    return 0;
}
