?????????
      +----------
NJXTL | QNYULHQLY
       -HFPYG
        =====
         QWQFH
        -HFPYG
         =====
         NNUNGQ
        -NMHJPF
         ======
          NRJNFL
         -NYPWWH
          ======
            PJGJY
           -QUYNU
            =====
            ?????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: medium