How to find Current Apllication Users Count

SELECT DISTINCT count(*)
FROM apps.fnd_user fu,
  apps.fnd_responsibility fr,
  apps.icx_sessions ic
WHERE fu.user_id          = ic.user_id
AND fr.responsibility_id  = ic.responsibility_id
AND ic.disabled_flag      ='N'
and IC.RESPONSIBILITY_ID is not null
AND ic.last_connect       > sysdate - (ic.time_out/60)/96;