?????????
      +----------
RPHMJ | QGNJNEMFU
       -QPYFTU
        ======
         PMRNFM
        -MYURFE
         ======
          PJHEPF
         -PQFTRH
          ======
           MQYUJU
          -MQQYEP
           ======
           ??????

base: 13
letters: EFGHJMNPQRTUY
difficulty: medium