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