CREATE TABLE table_27155243_3 (total__number VARCHAR(255), written_by VARCHAR(255), directed_by VARCHAR(255))
How many different episode numbers does the episode written by Sheri Elwood and directed by Jim Allodi have?
    
SQL: SELECT COUNT(total__number) FROM table_27155243_3 WHERE written_by = "Sheri Elwood" AND directed_by = "Jim Allodi"