How many different neighborhoods are there in Roseland community?
Roseland community refers to community_area_name = 'Roseland'
SELECT SUM(CASE WHEN T1.community_area_name = 'Roseland' THEN 1 ELSE 0 END) FROM Community_Area AS T1 INNER JOIN Neighborhood AS T2 ON T1.community_area_no = T2.community_area_no