|No.|Name|Term of Office|President(s) served under|
|---|---|---|---|
|1|William Bennett|1989 – 1991|George H. W. Bush|
|2|Bob Martinez|March 28, 1991 - January 20, 1993|George H. W. Bush|
|3|Lee P. Brown|January 1993 – December 12, 1995|Bill Clinton|
|4|Barry McCaffrey|February 29, 1996 – January 4, 2001|Bill Clinton|
|5|John P. Walters|December 7, 2001 – January 19, 2009|George W. Bush|
|6|Gil Kerlikowske|May 7, 2009 – March 6, 2014|Barack Obama|
|Acting|Michael Botticelli|March 6, 2014 –|Barack Obama|

Question: how many directors served more than 3 years?
Answer: 3