date		day	dur	workday				OUTPUT
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27-Nov-08	thu	3	workday(27-Nov-08,3)		02-Dec-08
29-Nov-08	Sat	2	workday(29-Nov-08,-2)		27-Nov-08
29-Nov-08	Sat	-1	workday(29-Nov-08,-1)		28-Nov-08
29-Nov-08	Sat	0	workday(29-Nov-08,0)		29-Nov-08
29-Nov-08	Sat	1	workday(29-Nov-08,1)		01-Dec-08
29-Nov-08	Sat	2	workday(29-Nov-08,2)		02-Dec-08
29-Nov-08	Sat	2	workday(29-Nov-08,10)		12-Dec-08