import java.util.Scanner

object Main extends App  {
  val sc = new Scanner(System.in)

  val a = sc.next
  val b = sc.next

  val res = (a,b) match{
    case ("H","H") => "H"
    case ("H","D") => "D"
    case ("D","H") => "D"
    case ("D","D") => "H"
  }

  println(res)
}