????????
      +---------
JRHHX | LNPNFUUR
       -JRHHX
        =====
        FTUPTU
       -FFRTML
        ======
         HHTEYU
        -HYHXFF
         ======
          XFHTTR
         -XFEJHU
          ======
          ??????

base: 13
letters: EFHJLMNPRTUXY
difficulty: medium