Set value in a specific cell

Hi,
I have two columns and would like to find the the value from the second column which does not exist in the first one and add it to the first empty cell in the column 1. for example, in the table below, I want to add ID 55555 from column ID 2 to the forth row in column ID 1. I know how to find the first empty cell in column 1, I just dont know how to tell excel to set A5 to value in B4

ID 1 ID 2 First Empty Cell
12243 12243 A$5$
3254346 3254346
546574 55555

2022-08-05 21_55_35-data - Excel.png

Are you wanting to do this with VBA?
Or are you saying that you want a formula to put in cell A5 to get the first value in COL B that is not already in COL A?

Are you still on V2010? If not, please update your profile.

I don't think this will work in V2010, but maybe. You might need to enter it using Ctrl, Shift, Enter as an array formula.

In A5, you could enter this formula:

=INDEX(B2:B4,MATCH(0,COUNTIFS(A2:A4,B2:B4),0))

Thank you very much.
That worked

You're welcome, and thanks for the rep.