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: Wrong Answer)

n = input()
max_ = 0
m = 0
for i in range(len(n)):
    if n[i] == "A" or n[i] == "C" or n[i] == "T" or n[i] == "G":
        m += 1
        if i == len(n) - 1:
            max_ = max(m,max_)
    else:
        max_ = max(m,max_)
        m = 0
print(max_)