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(input) {
  var helix = {
    "A": "T",
    "T": "A",
    "C": "G",
    "G": "C"
  };
  var count = 0;
  var maxCount = 0;
  for ( var i = 0; i < input.length; i++) {
    if(helix[input[i]]) {
      count++;
    } else {
      if ( maxCount <= count){
        maxCount = count;
      }
      count = 0;
    }
  }
  if(maxCount <= count) {
    maxCount = count;
  }
  console.log(maxCount);
}

process.stdin.setEncoding('utf-8');
process.stdin.on('data', function(data){
  Main(data.trim());
});