Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_77 (goal_difference INTEGER, losses VARCHAR, points VARCHAR, club VARCHAR)
### Question:
Which Goal Difference has 28 Points, and a Club of cd cartagena, more than 15 losses?
### Answer:
SELECT MAX(goal_difference) FROM table_name_77 WHERE points = 28 AND club = "cd cartagena" AND losses > 15