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 Ruby (2.7.1) (judge verdict: Runtime Error)

n,m=gets.split.map(&:to_i)
h=gets.split.map(&:to_i)
lines = []
while line = gets
    lines << line.chomp.split(' ').map(&:to_i)
end

onoffstr="off "*m
onoff=onoffstr.split.map(&:to_s)
lines.each do |line|
line.each_cons(2) do |x,y|
if h[x-1]<h[y-1]
onoff[y-1]="on"
onoff[x=1]="off"
end
end
end

puts onoff.count("on")