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_28 (complement VARCHAR, commander VARCHAR)
### Question:
What is the sum of complement commander Valkenburg received?
### Answer:
SELECT COUNT(complement) FROM table_name_28 WHERE commander = "valkenburg"