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