Oracle scheduler, set repeat_interval to run job at exactly date and time?

I have question regarding Oracle scheduler. How to set repeat_interval to run job on example, two times per month, at exact time? On example: 5th in month, at 09:00 and 20th in month, at 14:00 Is it possible without creating two jobs? I am trying to set scheduler and I have specific needs for my customers, which include example like this.