Formula/Function Question

I have a data field that captures todays date; along with a data field that captures a time horizon of 36 months, or 60 months, etc.  I am trying to get the report to capture today's date plus  the 36 months(example) and then subtract 30 days(1 Month).  Example, If today is 10/1/2014, and my time horizon is 36 months, the report would return 9/1/2017.

Thanks

Ryan