Bokura wa Minna Kawaisou [TV]

Usa, a high-school student aspiring to begin a bachelor lifestyle, moves into a new apartment only to discover that he not only shares a room with a perverted roommate that has an obsession for underaged girls, but also that another girl, Ritsu, a love-at-first-sight, is living in the same building as well!
Read more at http://myanimelist.net/anime/21405/Bokura_wa_Minna_Kawaisou#QluYKCUovRcLuded.99