Generate Unique Number

[punit83]

Hello To All,

Need Formula to generate and apply unique number for "Import" or "Purchase" to create a sequence series.
For export i want to apply original unique number which i can find by index & match.
Attaching Table for the reference.
Thank you in advance.

STATUS	LOCATION	UNIQUE.#	SHAPE	PCS	RATE	AMOUNT
PURCHASE	HONG KONG	1	APPLE	10	1.00	10.00
IMPORT	USA	2	MANGO	11	1.10	12.10
IMPORT	INDIA	3	GRAPES	12	1.20	14.40
IMPORT	INDIA	4	MANGO	13	1.30	16.90
IMPORT	INDIA	5	APPLE	14	1.40	19.60
EXPORT	USA	3	GRAPES	8	2.00	16.00
EXPORT	USA	4	MANGO	9	2.00	18.00
EXPORT	USA	5	APPLE	10	2.00	20.00
IMPORT	INDIA	6	GRAPES	6	1.60	9.60
IMPORT	INDIA	7	MANGO	5	1.70	8.50
IMPORT	INDIA	8	APPLE	4	1.80	7.20
IMPORT	INDIA	9	GRAPES	3	1.90	5.70
IMPORT	INDIA	10	MANGO	2	1.10	2.20
IMPORT	INDIA	11	APPLE	1	1.10	1.10