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 read<T: std::str::FromStr>() -> T{
    let mut a = String::new();
    io::stdin().read_line(&mut a).ok().unwrap();
    a.trim().parse().ok().unwrap()
}

fn pri<T: std::fmt::Display>(a : T){
    println!("{}", a);
}

fn main() {
    let te : String = read();
    let tet : &str = &te;
    match tet {
        "A" => pri("T"),
        "T" => pri("A"),
        "C" => pri("G"),
        "G" => pri("C"),
        _ => ()
    }
}