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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

checkATCG::String->String
checkATCG x = case x of
    "A" -> "T"
    "T" -> "A"
    "C" -> "G"
    "G" -> "C"

main::IO ()
main = do
    b <- getLine
    putStrLn $ checkATCG b