@BDM130 read how they define harem by clicking on the tag. main girl shows clear interest, while the sisters are "potentially" interested (the older one deeming him to be "wonderful", the younger one showing the "little-girl-in-love" type of crush in some panels). that makes three. but with all things in life it's highly debatable of course.
@Siquall The covers look so good right. Last august I went to Japan and bought all 3 volumes XD. Next month I'll visit Japan again and imma get the 4th one for sure.