countFS entries longest has_z (b:bs) =
  let
        len = length b
        longest' = max len longest
        entries' = entries + len
        has_zs = length (filter hasZEncoding b)
  in
        countFS entries' longest' (has_z + has_zs) bs
countFS entries longest has_z (b:bs) =
  let
        len = length b
        longest' = max len longest
        entries' = entries + len
        has_zs = length (filter hasZEncoding b)
  in
        countFS entries' longest' (has_z + has_zs) bs
countFS entries longest has_z (b:bs) =
  let
        len = length b
        longest' = max len longest
        entries' = entries + len
        has_zs = length (filter hasZEncoding b)
  in
        countFS entries' longest' (has_z + has_zs) bs