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_56 (losses INTEGER, team VARCHAR, goals_against VARCHAR)

### Question ###
What is the sum of the losses by the Montreal Hockey Club, who have more than 15 Goals Against?

### Accurate SQL ###

SELECT SUM(losses) FROM table_name_56 WHERE team = "montreal hockey club" AND goals_against > 15