Among the devices with an event occurring in 2016, how many of them are owned by a user in the M23-26 user group?
in 2016 refers to year(timestamp) = 2016; M23-26 user group refers to `group` = 'M23-26';
SELECT COUNT(T1.device_id) FROM gender_age AS T1 INNER JOIN events AS T2 ON T1.device_id = T2.device_id WHERE STRFTIME('%Y', T2.timestamp) = '2016' AND T1.`group` = 'M23-26'