Write SQL query to solve given problem: What is the sum of the number of pages of the books ordered by Mick Sever?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT SUM(T1.num_pages) FROM book AS T1 INNER JOIN order_line AS T2 ON T1.book_id = T2.book_id INNER JOIN cust_order AS T3 ON T3.order_id = T2.order_id INNER JOIN customer AS T4 ON T4.customer_id = T3.customer_id WHERE T4.first_name = 'Mick' AND T4.last_name = 'Sever'