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 JavaScript (Node.js 12.16.1) (judge verdict: Accepted)

const Main = (input) => {
    ans=''
    const lines = input.split('\r')
    for(i=0;i<lines.length;i++){
        if(lines[i].length===0 || lines[i]==='\n'){
            continue
        }
        line=lines[i].trim().split(" ")
        a=line[0]
        ans+=solve(a)+'\n'
    }
    ans=ans.trim()
    console.log(ans)
    return ans
}

function solve(a){
    if(a=='ABC'){
        return "ARC"
    }else if(a=='ARC'){
        return "ABC"
    }else {
        return "WA"
    }
}

Main(require('fs').readFileSync('/dev/stdin', 'utf8'))