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 Common Lisp (SBCL 2.0.3) (judge verdict: Accepted)

;;(declaim (optimize (speed 0) (safety 3) (debug 3)))
#+sbcl (declaim (sb-ext:unmuffle-conditions sb-ext:compiler-note))
(declaim (optimize (speed 3) (safety 0) (debug 0)))

(princ (if (string= (read-line) "ABC")
	   "ARC"
	 "ABC"))