What is the total number of patient portayers for the episode directed by Craig Zisk and written by Brad Falchuk?
create table table_26561508_1 (patient_portrayer varchar, directed_by varchar, written_by varchar, PRIMARY KEY (patient_portrayer))
select count(patient_portrayer) from table_26561508_1 where directed_by = "craig zisk" and written_by = "brad falchuk"