????????
      +---------
NHWNT | TUUYUXGM
       -NHWNT
        =====
        PMRMLX
       -PMZYWG
        ======
          UXNGG
         -NHWNT
          =====
          PZQWQM
         -PPMJYX
          ======
          ??????

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
hints: T << G
missing: V