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: Wrong Answer)

function main (sdi) {
  var input = sdi.trim();
  var a = input.match(/[ACTG]+/g);
  var loop = a ? a.length : 0;
  var length = 0;
  var r = "";
  for(var i=0; i<loop; i++){
    if(a[i].length > length){
      length = a[i].length;
    }
  }
  console.log(length);
}

main(require('fs').readFileSync('/dev/stdin', 'UTF-8'));