Find duplicates items in combine columns in Microsoft Excel

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Dates in column A Text in Column B
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03/10/2003 AAA
03/15/2003 BBB
03/20/2003 CCC
03/25/2003 AAA
03/30/2003 BBB
04/04/2003 CCC
03/25/2003 AAA
03/30/2003 BBB
04/04/2003 CCC
03/25/2003 AAA
03/30/2003 BBB
04/04/2003 CCC



Enter the formula : =A1&B1 to cell C1 and copy / paste the formula to cells C2:C12

Enter the formula : =IF(COUNTIF($C$1:C1,C1)>1,"Duplicate","Unique")
to cell E1 and copy / paste the formula to cells E2:E12