????????
      +---------
GRMXU | NTPFJNHL
       -JWHLR
        =====
         TUUUN
        -GRMXU
         =====
         GTYRFH
        -GYMMYH
         ======
          GXMRQL
         -GYMMYH
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard