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 main() {
    let a = read();
    let b = read();

    if a == b {
        println!("H");
    } else {
        println!("D");
    }
}

// fn read_v() -> Vec<char> {
//     let s = stdin();
//     //    let mut s = BufReader::new(s.lock());
//     let b = s.bytes()
//         .map(|c| c.unwrap() as char)
//         .take_while(|c| !c.is_whitespace())
//         .collect();
//     b
// }

// fn read_t() -> (u32, u32) {
//     let mut s = String::new();
//     stdin().read_line(&mut s).expect("failed read_t");
//     let mut i = s.split_whitespace().map(|c| c.parse().ok().unwrap());
//     (i.next().unwrap(), i.next().unwrap())
// }

fn read() -> char {
    let s = stdin();
    //    let mut s = BufReader::new(s.lock());
    let b = s.bytes()
        .map(|c| c.unwrap() as char)
        .take_while(|c| !c.is_whitespace())
        .collect::<Vec<char>>();
    b[0]
    // b.parse().ok().expect("read() failed")
}