(Program
{+(LowAnd
  {+(Send
    {+(Identifier)+})+}
  {+(Send
    {+(Identifier)+})+})+}
{-(LowOr
  {-(Send
    {-(Identifier)-})-}
  {-(Send
    {-(Identifier)-})-})-}
{-(LowAnd
  {-(LowOr
    {-(Send
      {-(Identifier)-})-}
    {-(Send
      {-(Identifier)-})-})-}
  {-(Send
    {-(Identifier)-})-})-})