This apartment building is shown as number 10. Actually it is still number 10a. This and the other apartment building straight to east are both 10a. To the one on the east is 10a A and the one on the west is 10a B.

Why is this named liked this? The plot for the 10a buildings was originally part of the 10 to the north. The plot was split but since the buildings had already been numbered, postfix "a" was appended to create a new address.