Among the players who went to high school in Chicago, how many of them belongs to the west conference?
high school in Chicago refers to hsCity = 'Chicago'; belong to the west conference refers to divID = 'WE'
SELECT COUNT(DISTINCT T1.playerID) FROM players AS T1 INNER JOIN player_allstar AS T2 ON T1.playerID = T2.playerID WHERE T1.hsCity = 'Chicago' AND T2.conference = 'West'