object Main extends App {
  val sc = new java.util.Scanner(System.in)
  var a = sc.next.sorted
  for (i <- 0 until a.length - 1 if i % 2 == 0){
    if (a(i) != a(i+1)){
      println("No")
      sys.exit()
    }
  }
  println("Yes")
}
