Round to the First of the Month

Hello Excel masters! I am trying to figure out how to round to the first of the next month UNLESS the date entered in A1 is already the first of the month.
Example:
A1 = 6/2/2015 I need B1 to = 7/1/2015
A1 = 6/1/2015 I need B1 to = 6/1/2015

I know how to get the first part but I can't figure out the second. I'm hoping one of you can!

TIA!