closing man and help buffers

[Luca Ferrari]

Hi all,
this should be trivial, but I have not found a solution yet: often I
open a man buffer (M-x man) or an help buffer (e.g., C-h something).
The behavior is that the window splits and the buffer I was currently
editing keeps the focus, so to close the other informational buffer I
have to either use C-x C-b or switch to the buffer and kill it. Is
there a smarter way to close such buffer (and only it) while keep the
focus on the editing one? Something like "close the last opened
buffer" could work.

Thanks,
Luca