Calendar Date Range - Director Lingo

Does anybody know of any code for the following?

I want to put in a start date and then enter a second date which may be less than 1 year, I want the Lingo to count how many days are between the two dates. I could do it easily with a very large list of days and use a count between the two dates but this would not include leap years!!

Any infor would be great.

Thanks

Craig.