(Program
  (Comprehension
  { (Identifier)
  ->(Identifier) }
    (
      (
        (
        {+(Identifier)+}
        {-(Identifier)-})
      {+(Identifier)+}
      {-(Identifier)-})
    {+(
        (Call
          (Identifier)
          (Empty)))+}
    {+(
        (
          (Identifier))
        (Identifier))+}
    {+(
        (Call
          (Identifier)
          (Empty)))+}))
  (Comprehension
  { (Identifier)
  ->(Plus
      (Identifier)
      (Integer)) }
    (
      (
        (
        {+(Identifier)+}
        {-(Identifier)-})
      {+(Identifier)+}
      {-(Identifier)-})
    {-(
        (Identifier))-})))