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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<cmath>
#include<cstdlib>
#include<string>
#include<cstring>
#include<algorithm>
#include<vector>
#include<map>
#include<iomanip>
#include<queue>

using namespace std;

typedef long long ll;

typedef std::pair<int, int> ipair;
bool lessPair(const ipair& l, const ipair& r){return l.second < r.second;}
bool morePair(const ipair& l, const ipair& r){return l.second > r.second;}

template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

const ll MOD = 1e9 + 7;
// const long long INF = 1LL<<60;
void add(long long &a, long long b) { a += b; if (a >= MOD) a -= MOD; }
void sub(long long &a, long long b) { a -= b; if (a < 0) a += MOD; }
void mul(long long &a, long long b) { a *= b; a %= MOD; }
ll llmin(ll a, ll b) { if (a < b) return a; else return b; }
ll llmax(ll a, ll b) { if (a < b) return b; else return a; }
ll llabs(ll a) { if (a >= 0) return a; else return - a; }
ll llmodpow(ll a, ll n) {
   if (n == 0) return 1;
   ll tmp = llmodpow(a, n / 2);
   mul(tmp, tmp);
   if (n & 1) mul(tmp, a);
   return tmp;
}

int main() {
   char a, b;
   cin >> a >> b;
   if (a == b) cout << 'H' << endl;
   else cout << 'D' << endl;
   return 0;
}