RULE IHAN WA IKU MADE H!?: OSANANAJIMI TO DOUKYO HAJIMEMASHITA

Yuki decided to live alone when she got a job. However due to a mistake in the contract she has to live with Keita, her childhood friend! The two of them then established a set of rules for their cohabitation life together but there's a penalty if one break the rules! What's the penalty?!