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