#include<stdio.h>
#include<string.h>
int main()
{
    int res;
    char s[100] ;
    gets(s) ;
    res=strcmp(s,"ABC") ;
    if(res==0)
        //cout<<"ARC"<<endl ;
        printf("ARC\n");
    else if(res!=0)
        printf("ABC\n");

    return 0;

}
