(Program
  (If
  { (Identifier)
  ->(Identifier) }
    (
    { (Identifier)
    ->(Identifier) }
    { (Identifier)
    ->(Identifier) })
  { (Empty)
  ->(If
    {+(Identifier)+}
    {+(
      {+(Identifier)+}
      {+(Identifier)+})+}
    {+(
      {+(Identifier)+}
      {+(Identifier)+})+}) }))