Score : 100 points
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.
A, C, G and T.Input is given from Standard Input in the following format:
b
Print the letter representing the base that bonds with the base b.
A
T
G
C