Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Name | State of residence | Took office | Left office | President served under |
| --- | --- | --- | --- | --- |
| Karl Rove | Texas | January 21, 2001 | August 31, 2007 | George W. Bush |
| Barry Steven Jackson | Ohio | September 1, 2007 | January 19, 2009 | George W. Bush |
| Pete Rouse | South Dakota | January 20, 2009 | October 1, 2010 | Barack Obama |
| David Axelrod | Illinois | January 20, 2009 | January 10, 2011 | Barack Obama |
| David Plouffe | Delaware | January 10, 2011 | January 25, 2013 | Barack Obama |
| Valerie Jarrett | Illinois | January 20, 2009 | present | Barack Obama |
| Daniel Pfeiffer | Delaware | January 25, 2013 | present | Barack Obama |
Question:
how many advisors were in office for less than 3 years?
Answer:
4