????????
      +---------
FHEJJ | HWXXXLGX
       -FHEJJ
        =====
        EPGRRL
       -EUJPMM
        ======
         PWMPMG
        -PFXXWT
         ======
          PTFXPX
         -PFXXWT
          ======
          ??????

base: 13
letters: EFGHJLMPRTUWX
difficulty: hard