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_203_591 ( id number, "high school" text, "join\nyear" text, "from" text, "left" text, "league left to" text )

### Question ###
how many high schools had a league leave to big nine conference ?

### Accurate SQL ###

SELECT COUNT("high school") FROM table_203_591 WHERE "league left to" = 'big nine conference'