This calendar app works completely offline.
If I delete the app, the schedule and contacts I wrote down here are gone.

・You can create a contact book that is only used within the app.
・You can also write down your income and expenditure schedule in the schedule.
・You can also view income and expenditure data for each period.

This calendar app is perfect for managing side job schedules, information about people you meet on matching apps, and other secret schedule management.