C****  THE USE OF THIS PROGRAM IS DESCRIBED IN A BOOK 
C****  TITLED "SIMULATION WITH GASP II" BY PRITSKER AND
C****  KIVIAT.
C****  
C****  THE ROUTINE TO READ INPUT DATA IS NAMED DATAN IN THE BOOK
C****  AND HAS BEEN CHANGED TO DATIN IN ORDER NOT TO DUPLICATE
C****  A FUNCTION NAMED DATAN.
C****  
C****  THE ROUTINE DRAND IS INSTALLATION DEPENDENT, AS A RANDOM 
C****  NUMBER IS GENERATED FROM THIS ROUTINE. EACH INSTALLATION MUST
C****  MODIFY THE CODING TO CALL THEIR OWN RANDOM NUMBER GENERATOR.