LCQ
      +--------
MGNXQ | NGTNNCF
       -MGNXQ
        =====
        LXNNXC
       -LMNGXC
        ======
         TYMYYF
        -PNYNQQ
         ======
          PTCGH

base: 12
letters: CFGHLMNPQTXY
difficulty: medium
missing: H