object Main extends App {
  import scala.annotation.tailrec
  
  @tailrec
  def help(s:Array[String],t:Array[String]):Array{String] = {
    if (s.length==0) t else help(s.drop(2),t+s(0))
  }
  val s = readLine.toArray
  println(help(s,Array("")).mkString)
}