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 Scala (2.11.7) (judge verdict: Accepted)

import scala.io.StdIn

object Main {

  def cmp: PartialFunction[Char, Char] = {
    case 'A' => 'T'
    case 'G' => 'C'
    case 'C' => 'G'
    case _   => 'A'
  }

  def main(args: Array[String]): Unit = {

    val b = StdIn.readChar()
    val ans = cmp(b)
    println(ans)
  }

}