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_12148147_2 ( third_year VARCHAR, first_year VARCHAR )

### Question ###
How many classes are taken in the third year when pag-unawa was taken in the first year?

### Accurate SQL ###

SELECT COUNT(third_year) FROM table_12148147_2 WHERE first_year = "Pag-unawa"