PHHN
      +---------
VJZPW | JJPLLURH
       -VJZPW
        =====
        MZXNUU
       -MTMNQV
        ======
         MQZNYR
        -MTMNQV
         ======
          UTZZMH
         -UMTHLV
          ======
           WNWJX

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: G