I use the Vlookup()  I remember this like this

=VLOOKUP([look_up_this],[in_this_range],[tell_me_this[coloum_count]1,2,3],[false]=not Sorted)

do some checking once right

highlight the coloum and copy it the paste special value back to it self then it look like you have done the data enter

Had some ask me how can I find the Dups in a list of number items in a list with out sorting them. mmmmmmmmmmmm

thinking ................

so this is what I told him why not count the number of items in a list

the formala would be =Countif([range],[cell_to_check])

you must put the $ in the [range]

ie =countif($A$4:$A$1000,A4) it will put a 1 in the formula cell and if more than 1 put the count of it.