Adjusting an array formula to not count blank spaces.

OK so I have added a code in VBA to the workbook to support this formula:

=SUM(IF(FREQUENCY(IF(V(arrayunion('JAN'!C3:C36,'FEB'!C6:C36,'MAR'!C6:C36))<>"",MATCH(V(),V(),0)),ROW(INDIRECT("1:"&COLUMNS(V())))),1))

This formula is for a Quarterly report that gives only the individual residents for the 3 month period (each month is on a separate worksheet) So if someone stayed in January and again in March, they should only be counted once.

This formula is returning a count of 1 more than the actual number of individuals. Is it possible that it is counting blank spaces as 1? If so how do I fix the formula?
Cheers.

Oh this is a silly mistake. It is a typo. the formula is searching worksheet jan! C3:C36. It should be C6:C36.
Thanks anyway.