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 JavaScript (node.js v5.12) (judge verdict: Accepted)

function Main(input){
  A = input.trim();
  ans = '';
  switch(A){
    case 'A' : ans = 'T';break;
    case 'T' : ans = 'A';break;
    case 'G' : ans = 'C';break;
    case 'C' : ans = 'G';break;
    default : break;
  }
  console.log(ans);
}

Main(require("fs").readFileSync("/dev/stdin","utf-8"));