????????
      +---------
FXEHF | XLXUXPUX
       -FXEHF
        =====
        TXRMTP
       -TTYMPN
        ======
         FFHLPU
        -FTTPFR
         ======
          TQHULX
         -TWPREP
          ======
          ??????

base: 14
letters: EFHLMNPQRTUWXY
difficulty: medium