#include <bits/stdc++.h>
using namespace std;
// https://atcoder.jp/contests/abc166/tasks/abc166_a
int main()
{
    string in;
    cin >> in;

    if(strcmp("ABC",in.c_str())==0)
    {
        printf("ARC\n");
    }
    else
    {
        printf("ABC\n");

    }
    return 0;
}
