Question: Two of London's 33 districts are cities: the City of London (the historic centre including Smithfield and Holborn) and which other?
Sentence (from "Districts of England"): There are a total of 326 districts made up of 36 metropolitan boroughs, 32 London boroughs, 201 non-metropolitan districts, 55 unitary authorities, as well as the City of London and the Isles of Scilly which are also districts, but do not correspond to any of these categories.
Relevant evidence: No