Problem:
Score : 100 points

Problem Statement

AtCoder Inc. holds a contest every Saturday.

There are two types of contests called ABC and ARC, and just one of them is held at a time.

The company holds these two types of contests alternately: an ARC follows an ABC and vice versa.

Given a string S representing the type of the contest held last week, print the string representing the type of the contest held this week.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in PyPy2 (7.3.0) (judge verdict: Runtime Error)

    s = raw_input()
    # a, b = s.split(' ')
    # a, b = int(a), int(b)


    def mul(s):
        if s != "ARC" or s != "ABC":
            return None
        return {"ARC":"ABC","ABC":"ARC"}[s]

    print mul(s)