Jenn Bard, who lives in the San Francisco Bay area, commutes by car from home to work. She knows that it takes her an average of 28 minutes for this commute in the morning. However, due to the variability in the traffic situation every morning, the standard deviation of these commutes is 5 minutes. Jenn has to be at work by 8:30 A.M. every morning. By what time must she leave home in the morning so that she is late for work at most 1% of the time?