????????
      ----------
LRJPM ) JJRQQJLU
       -PWTYQX
        ======
         XLRWWL
        -XXMMJU
         ======
          XPXLPU
         -JMQXYW
          ======
          ??????

base: 12
symbols: CJLMPQRTUWXY
missing: C
difficulty: medium