http://www.mangago.me/read-manga/gareki_no_rakuen/mf/v01/c003/71/
it's a novel (Takumi na Sogekishiyu by Miyu Matsuda & Nara Chiharu)
Thanks
http://www.mangago.me/read-manga/gareki_no_rakuen/mf/v01/c003/71/