????????
      +---------
MQRPP | CNNUMWPC
       -CXPPW
        =====
         CNUCW
        -CXPPW
         =====
          CUNXP
         -CXPPW
          =====
           WNMRC
          -NCRPN
           =====
           ?????

base: 9
letters: CMNPQRUWX
difficulty: medium