HPJ
      +--------
QULQH | MLHLHWY
       -XWHWT
        =====
        QJPJTW
       -QMHJRT
        ======
         QXFWMY
        -QGXLQF
         ======
          QWNTY

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: medium
missing: N