Vlookups and array formulas

Hello I have two columns in excel:
Column A (A2:A56) contains contract codes values
Column B(b2:b56) contains renewed contract codes values

I would like to count the number of contract codes values that have been renewed (matching Column B with Column A). I would like to achieve that without adding a column (altering my structure)

Is it possible to achieve that by using array formulas

(If I add a column and I perform a vlookup then I can straightforward count the number of matches)

My Array Formula looks as follows (My aim is to count the number of cells in column B3:B9 that do not return an error(have a match) with a cell in column A3:A9

=SUM(IF(ISERROR((VLOOKUP(OFFSET($B$3,ROW($B$3:$B$9)-ROW($B$3),0),$A$3:$A$9,1,FALSE))),0,1))

To clarify please see attachment
Many Thanks