Marriage Purple

15 year old Suzumiya Rin managed to get into the high school she wanted but is reunited with the tyrant Sakamato Yuuchi who used to boss her around in grade school. Yuuchi asked Rin to sign a note, knowing it's better not to resist she reluctantly signed it not knowing that note was actually a marriage registration form?! Realizing this, Rin demanded the registration to be taken back, Yuuchi only agrees under the condition that she remains by his side for 3 years?! (Source: Hakusensha, translated) Note: Includes one extra chapter.