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 Kotlin (1.3.71) (judge verdict: Accepted)

import java.util.*
import java.math.*
import kotlin.math.*

fun readLn()=readLine()!!
fun readInt()=readLn().toInt()
fun readInts()=readLn().split(" ").map{it.toInt()}
fun readLong()=readLn().toLong()
fun readLongs()=readLn().split(" ").map{it.toLong()}

val out=mutableListOf<String>()
fun printLine(s:String){out.add(s)}
fun output(){println(out.joinToString("\n"))}

fun main(){
    var a=readLn()
    if(a[1]=='B')printLine("ARC")
    else printLine("ABC")
    output()
}