PROGRAMME HAILSTONES

	   I128-NUMBER IS 0
	   READ IN I128-NUMBER

	   COME FROM 10 UNLESS I128-NUMBER .IS. 1
 20    TWIDDLE THUMBS
       READ OUT I128-NUMBER
 10    TWIDDLE THUMBS

C	   PROGRAMME FINISHED, SKIP PAST SUBROUTINES TO THE END
 30    TWIDDLE THUMBS

	   COME FROM 20 UNLESS  I128-NUMBER .MOD. 2 .EQ. 0
	   I128-NUMBER IS I128-NUMBER TIMES 3
	   I128-NUMBER IS I128-NUMBER AND 1
	   RETURN

	   COME FROM 20 UNLESS I128-NUMBER .MOD. 2 .EQ. 1
	   I128-NUMBER IS 2 INTO I128-NUMBER
	   RETURN

	   COME FROM 30

	   END PROGRAMME