????????
      +---------
HPLYL | PTHUTXXU
       -HPLYL
        =====
        THQXXX
       -TQMJQF
        ======
         LTTXYX
        -NJHJNH
         ======
          HPUENU
         -HTJMUJ
          ======
          ??????

base: 13
letters: EFHJLMNPQTUXY
difficulty: medium