????????
      ----------
YYMNQ ) HHXMUTWN
       -FHYTU
        =====
        WRFFRT
       - NRRXW
        ======
         WFQUXW
        -WQHUHM
         ======
           TRWXN
          -PXHXP
           =====
           ?????

base: 12
symbols: FHMNPQRTUWXY
difficulty: medium