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 Python (3.8.2) (judge verdict: Runtime Error)

n=input()
l=list(map(int,input().split()))
x=0
c=list()
for i in range(1,n+1):
  a=i+l[i-1]
  c.append(a)
  b=i-l[i-1]
  if b in c:
    x=x+c.count(b)
print(x)