Rank based on Date Value, and Vlookup from several sheets

[ANALYSTBANK]

I have date data in Column O, which appears like. At any given point in time, i would have such date data for 5 to 10 days, and I want to just assign 1 to first date, and next date to 2 and so on.

What formula (can i use RANK formula, and how) I can use to get the desired result. SEcond part of the query may require macro, so will ask later.

Basic Data Desired Output
Column O Column P
20-Jan-13 1
20-Jan-13 1
20-Jan-13 1
20-Jan-13 1

21-Jan-13 2
21-Jan-13 2
21-Jan-13 2
21-Jan-13 2
21-Jan-13 2

22-Jan-13 3
22-Jan-13 3
22-Jan-13 3
22-Jan-13 3

26-Jan-13 4
26-Jan-13 4
26-Jan-13 4
26-Jan-13 4


Thanks

 

[ANALYSTBANK]

I just found the like logical way. I'll put value 1 in first row, then compare dates, if same, put value 1 from previous cell, else previous cell value which is 1, + 1, and I'll get d desired result, and fill subsequent cells