????????
      +---------
GNGCU | XJGTLXUN
       -XPCPU
        =====
         PJCLX
        -XPCPU
         =====
         GWUPXU
        -GXTJTU
         ======
          GXPNUN
         -GGJLPU
          ======
          ??????

base: 10
letters: CGJLNPTUWX
difficulty: intermediate