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 invoices (customer_id VARCHAR); CREATE TABLE customers (id VARCHAR, first_name VARCHAR, last_name VARCHAR)
### Question:
How many orders does Lucas Mancini has?
### Answer:
SELECT COUNT(*) FROM customers AS T1 JOIN invoices AS T2 ON T1.id = T2.customer_id WHERE T1.first_name = "Lucas" AND T1.last_name = "Mancini"