????????
      +---------
EPLMW | LEENFFQH
       -WMHEQ
        =====
        MMNWEF
       - NQMHC
        ======
         QLHCLQ
        -QHFLQC
         ======
          QNMHHH
         -QLWHHH
          ======
          ??????

base: 10
letters: CEFHLMNPQW
difficulty: medium