Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_86 (format VARCHAR, region_4 VARCHAR, _number_episodes VARCHAR, _number_disc_s_ VARCHAR)

### Question ###
What was the format for the 4 disc season that had less than 22 episodes and n/a for region 4?

### Accurate SQL ###

SELECT format FROM table_name_86 WHERE _number_episodes < 22 AND _number_disc_s_ = 4 AND region_4 = "n/a"