????????
      +---------
PQWGH | XLUULYNX
       -PQWGH
        =====
        QMPRNY
       -QYQWFX
        ======
         QRYWUN
        - HTFXF
         ======
          QRLJWX
         - HTFXF
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: easy