Problem:
Score : 100 points

Problem Statement

Two deer, AtCoDeer and TopCoDeer, are playing a game called Honest or Dishonest.
In this game, an honest player always tells the truth, and an dishonest player always tell lies.
You are given two characters a and b as the input. Each of them is either H or D, and carries the following information:

If a=H, AtCoDeer is honest; if a=D, AtCoDeer is dishonest.
If b=H, AtCoDeer is saying that TopCoDeer is honest; if b=D, AtCoDeer is saying that TopCoDeer is dishonest.

Given this information, determine whether TopCoDeer is honest.

Constraints

a=H or a=D.

b=H or b=D.

Input

The input is given from Standard Input in the following format:

a b

Output

If TopCoDeer is honest, print H. If he is dishonest, print D.

Sample Input 1

H H

Sample Output 1

H

In this input, AtCoDeer is honest. Hence, as he says, TopCoDeer is honest.

Sample Input 2

D H

Sample Output 2

D

In this input, AtCoDeer is dishonest. Hence, contrary to what he says, TopCoDeer is dishonest.

Sample Input 3

D D

Sample Output 3

H

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn read_line()-> String {
    let mut s = String::new();
    let _ = io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main () {
	let s = read_line();
	let s2 = s.split_whitespace().collect::<Vec<&str>>();
	let atd = s2[0];
	let tcd = s2[1];
	let r = ans(&atd,&tcd);
	println!("{}",r);
}
fn ans(atd: &str,tcd: &str) -> &'static str {
	if atd == "H" {
		if tcd == "H" {
			"H"
		}else {
			"D"
		}
	}else {
		if tcd == "H" {
			"D"
		}else {
			"H"
		}
	}
}