 If there are "n" different bytes (symbols) used in the uncompressed data, then the Huffman code will consist of two RLE codes (RUNA and RUNB), "n" − 1 symbol codes and one end-of-stream code.Because of the combined result of the MTF and RLE encodings in the previous two steps, there is never any need to explicitly reference the first symbol in the MTF table (would be zero in the ordinary MTF), thus saving one symbol for the end-of-stream marker (and explaining why only "n" − 1 symbols are coded in the Huffman tree).In the extreme case where only one symbol is used in the uncompressed data, there will be no symbol codes at all in the Huffman tree, and the entire block will consist of RUNA and RUNB (implicitly repeating the single byte) and an end-of-stream marker with value 2.