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)

S = input()
longest_acgt = 0

def is_acgt(string):
    a_count = string.count("A")
    c_count = string.count("C")
    g_count = string.count("G")
    t_count = string.count("T")
    acgt_count = a_count + c_count + g_count + t_count
    string_count = len(string)
    if acgt_count == string_count:
        return True
    else:
        return False

for i in range(0, 11):
    # print(str(i) + "回目")

    
    for j in range(i + 1, 11):
        # print(str(i) + " " + str(j))
        # print(S[i:j])
        result = is_acgt(S[i:j])
        if result and len(S[i:j]) > longest_acgt:
            longest_acgt = len(S[i:j])
            pass
print(longest_acgt)