????????
      +---------
TTYMF | LYJMNLJF
       -FFNPR
        =====
        YRMYGL
       -YGGTLW
        ======
         YNPULJ
        -YJJHXR
         ======
          YRYYQF
         -YGGTLW
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard