Table: manager_changes_2008
Columns: team
outgoing_manager
manner_of_departure
date_of_vacancy
last_match
replaced_by

Question: Name the total number of date of vacancy for manner of departure being resigned and outgoing manager is geninho
SQL: SELECT COUNT("date_of_vacancy") FROM manager_changes_2008 WHERE "manner_of_departure" = 'Resigned' AND "outgoing_manager" = 'Geninho'