Crystal Reports Crystal DateDiff function

Message

   I'm using Crystal Reports 11.  I created a new function and trying to find the number of days between two dates.  What I'm getting in the result is a decimal... 4.00    I want to see 4, not 4.00
Here's my formula:

DateDiff("d", {Command.RESERVATION_START_DATE}, {Command.RESERVATION_END_DATE})+1

The variable names in the function are datetime, but I only want the # of days in integer form, not decimal.

I know the "d" should return the # of days between the dates, but it's not working for some reason (at least its not coming in the format I want...Integer.  I've tried INT and ToNumber in front of DateDiff, but no go.
The Reservation_start_date = 9/14/2013, end_date = 9/17/2013 and I want the result to be 4 because the reservation actually starts on 9/14... so the count would be 4...14,15,16,17  (and that's why I added + 1 on the end, otherwise I get 3. 