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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
fscanf(STDIN, "%s", $b);
function pare($b){
    if($b === 'A'){
        return 'T';
    }elseif($b === 'T'){
        return 'A';
    }elseif($b === 'C'){
        return 'G';
    }elseif($b === 'G'){
        return 'C';
    }
}
$answer = pare($b);
echo $answer;
?>