364.

This is my white door. I can see through it from the inside.



My door has been opened to friends, welcomed. My door has been opened by burglars, unwelcome.
I need two keys to open it. One lock is higher than the other one. The door doesn't have an opening knob on the outside. One of the locks opens it: The one above. The higher one is the most important. So I start to open the lower first, then the one above.

For everyone, the higher instance is always the most important to open.