Write SQL query to solve given problem: What is the biggest amount of payment for a rental made by Mary Smith?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.amount FROM payment AS T1 INNER JOIN customer AS T2 ON T1.customer_id = T2.customer_id WHERE T2.first_name = 'MARY' AND T2.last_name = 'SMITH' ORDER BY T1.amount DESC LIMIT 1