Initial release.

On the surface, this app looks like an ordinary calculator. But once you enter the default combination "2" "+" "3" and hit "=", you will immediately be greeted with a diary.
This diary is well hidden to the public eye except for you.

You can change the combination inside the app.
But beware, you need to remember your password well.

This is my first ever application, hence other improvement will come along the way in future.