Write SQL query to solve given problem: Among the devices on which an event happened on 2016/5/1, how many of them are used by a male user?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.device_id) FROM events AS T1 INNER JOIN gender_age AS T2 ON T1.device_id = T2.device_id WHERE T1.timestamp = '2016-05-01' AND T2.gender = 'M'