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