Air filters - location, replacement

I have a 2004 C200 Kompressor sedan (and not a C230 as indicated elsewhere  -  I was not given the option to choose C200).  The spare parts section at the MB dealer gave me a thin, white wafer-type filter as the pollen filter (air conditioner filter) and a fairly big cylindrical filter as the engine air intake filter.  My car has a flat filter above the battery and I was under the impression that's the air intake filter, but it appears as if it is the air conditioner and cabin intake filter.  Can anyone guide me on how and where to replace the air intake filter and where I'll find the pollen filter?  Are there more than one filter for the cabin / air conditioner?