(Statements
{+(Assignment
  {+(Identifier)+}
  {+(Integer)+})+}
  (Assignment
    (Statements
      (Identifier)
      (Identifier))
    (Statements
    {-(Integer)-}
      (Integer)
    {+(Integer)+}))
  (Assignment
  { (Identifier)
  ->(Identifier) }
  { (Integer)
  ->(Statements
    {+(Integer)+}
    {+(Integer)+}) })
{-(Assignment
  {-(Identifier)-}
  {-(Statements
    {-(Integer)-}
    {-(Integer)-})-})-})