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)

import math
from sys import stdin,stdout
#% 998244353
from heapq import heapify,heappop,heappush

import collections
# T = int(stdin.readline())
# for i in range(T):
    #N=int(stdin.readline())
N,M=list(map(int,stdin.readline().split()))
hill=list(map(int,stdin.readline().split()))

dc=collections.defaultdict(list)
#vis=set()
for m in range(M):
    A,B=list(map(int,stdin.readline().split()))
    dc[A].append(B)
    dc[B].append(A)

ans=0
for k,ls in dc.items():

    f=0
    z=0
    for h in ls:

        if hill[k-1]<=hill[h-1]:
            f=1
            break

    if not f:
      #  print(k)
        ans+=1  
#print(ans)
#ans+=(N-len(dc.keys()))
print(ans)