PROGRAM

 Begins a main program.  The PROGRAM statement is optional; when
 used, it can only be preceded by comment lines or an OPTIONS
 statement.  Statement format:

    PROGRAM nam

    nam   Is a symbolic name for the program.  The name must 
          be unique among all global names in the program.  

 If no PROGRAM statement begins the program, the program name
 defaults to filename$MAIN, where filename is the name of the file
 containing the program.

 The main program cannot contain the following attributes:  INTENT,
 OPTIONAL, PRIVATE, or PUBLIC.

 A main program can contain an internal subprogram (defines an
 internal procedure).  It must be preceded by a CONTAINS statement.