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 Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn main() {
  let mut input = String::new();

  io::stdin().read_line(&mut input)
    .expect("Failed to read line");

  let mut output = String::new();
  let input = input.trim_right();

  if input == "A" {
    output = "T".to_string();
  }
  else if input == "T" {
    output = "A".to_string();
  }
  else if input == "G" {
    output = "C".to_string();
  }
  else {
    output = "G".to_string();
  }


  println!("{}", output);
}