If statement with "left" condition applied to a date

Hi,

I want to identify, by looking at a date, if we are at the first half of the month or second half of the month as these employees are paid on the 15th or the 30 31st

I thought of applying the following formula to a cell containing the date 31/01/2008

If(left(A1;2)>15;"2nd Half";"1st Half"

But I get the result as 1st half. It seems this formula doesnt work for numeric vales.

Any ideas?
Thanks