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_12707313_2 ( constr VARCHAR, first_win VARCHAR )

### Question ###
Name the number of constr with the first win at the 1978 brazilian grand prix

### Accurate SQL ###

SELECT COUNT(constr) FROM table_12707313_2 WHERE first_win = "1978 Brazilian Grand Prix"