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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.Scanner;




class Main{


	static	ArrayList<Integer> one ;
	static	ArrayList<Integer> two ;
	static	ArrayList<Integer> three ;
	static	ArrayList<Integer> four ;

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);			//文字の入力
		String aString = sc.next();
		String bString = sc.next();

		if(aString.charAt(0) == 'H'){
			if(bString.charAt(0) == 'H'){
				System.out.println("H");
			}else{
				System.out.println("D");

			}
		}else{
			if(bString.charAt(0) == 'H'){
				System.out.println("D");
			}else{
				System.out.println("H");

			}
		}




	}
	
	
	
}

class Pair implements Comparable{
	Character from;
	int end;
	@Override
	public int compareTo(Object other) {
		Pair otherpair = (Pair)other;

		return end - otherpair.end;
	}
}