Problem:
Score : 100 points

Problem Statement

On the Planet AtCoder, there are four types of bases: A, C, G and T. A bonds with T, and C bonds with G.

You are given a letter b as input, which is A, C, G or T. Write a program that prints the letter representing the base that bonds with the base b.

Constraints

b is one of the letters A, C, G and T.

Input

Input is given from Standard Input in the following format:

b

Output

Print the letter representing the base that bonds with the base b.

Sample Input 1

A

Sample Output 1

T

Sample Input 2

G

Sample Output 2

C

Solution in Python (3.4.3) (judge verdict: Accepted)

def main():
    b = input()
    argc = len(b)
    data = []
    for i in range(argc):
#       print(b[i])
      if (b[i]=='A'):
        data.append('T')
      elif (b[i]=='T'):
        data.append('A')
      elif (b[i]=='C'):
        data.append('G')
      else:
        data.append('C')
    result = ''.join(data)
    print(result)
main()