How to tag levels when building is in a slope, and entrance is on the second level?

How should I tag a building in a slope, one level partially underground, and with an entrance on what would be the second level? Essentially how to tag the F part in the illustration below? Tag it as level 1, it would visualised as the same level as D, tag it as level 2 it would be either floating in air or take up two levels.

The question (and the image) presumably stems from Wiki description of key:level:

If the building is partially buried, level 0 will correspond to the lowest level that has a part above ground in order to remain consistent with the Simple 3D Buildings specification’s building:levels=* key.

According to this, amenities at floor D should be tagged with level=0, while those at F should be at level=1. The documentation trail further leads to Key:building:min_level, which has a photo of a building similar to yours, where building:min_level=1 (alternatively, use building:part:min_level=1 if you are going to model F as a building:part).