Require a function module to add days to a date?

My purpose is to add days to a particular date and get the resulting date. I tried using this function module "RP_CALC_DATE_IN_INTERVAL", but the problem is this function module only accepts two digits for days. i.e. i am only able to add a maximum of 99 days to a particular date, but i do want to go further and add more so please tell me if there is any function module which shall help me add 3 digit days to a date.