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)

import sys

S = list(input())

length = 0
maxlen = 0

for s in S:
	if s == 'A' or s == 'T' or s == 'C' or s == 'G' :
		length += 1
	else :
		if length > maxlen:
			maxlen = length
		length = 0

print(maxlen)