class List {
  def head() : Int = this.head();
  def tail() : List = this.tail();
  def printString() {
  }
  def printStringLn() {
    do this.printString();
    printChar(10);
  }
}

class Nil extends List {
}

class Cons extends List {
  val head : Int;
  val tail : List;
  def head() : Int = this.head;
  def tail() : List = this.tail;
  def printString() {
    printChar(this.head);
    do this.tail.printString();
  }
}

{
  do "Bonjour".printStringLn();
}