????????
      +---------
RPJNJ | MGLMXTQL
       -RPJNJ
        =====
        FHMQJT
       -HGURFY
        ======
         FLLFTQ
        -FLHFNG
         ======
           UYHHL
          -TXXGX
           =====
           ?????

base: 14
letters: FGHJLMNPQRTUXY
difficulty: challenging