Vba list up result in column depends upon date and code

I have data set contains date in b:b column parts code in c:c column

dear experts

i want result get in to d:d column from depends upon value of b & c


e.g

if 3/4/2013 is date and ert100 prodcode if ert100 is not exist in list then ert100 is one time entry
if ert100 is repeats more than once then check date 3/4/2013 is 1st entry
if again 4/4/2013 entry made against ert100 is 2nd entry
if again 12/4/2013 entry made against ert100 is 3rd entry.

So here consider first partcode against date first time is 1st entry more than once 2,3,4, entry

check the attachment you may understand than my explanation.

any one have solution for this????....

any excel expertise can help me outttttttttttttttttt???