Please list the area name of the communities in the Far north side, which has a population of more than 50000 but less than 70000.
area name refers to community_area_name; the Far north side refers to side = 'Far North'; a population of more than 50000 but less than 70000 refers to population BETWEEN '50000' AND '70000'
SELECT community_area_name, side FROM Community_Area WHERE side = 'Far North ' AND population BETWEEN 50000 AND 70000