????????
      +---------
WQXYW | MHXMEMXG
       -WQXYW
        =====
        GWJGNM
       -GUHWQJ
        ======
         HMQMMX
        -HXNMJW
         ======
          FGJMGG
         -FFTWGJ
          ======
          ??????

base: 14
letters: EFGHJMNQRTUWXY
difficulty: medium
missing: R