????????
      +---------
JUXGW | UJTTNHXY
       -JUXGW
        =====
        RHMHUH
       -RQPNTY
        ======
          PYMGX
         -MTWQR
          =====
           GXPTY
          -GRQLH
           =====
           ?????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
hints: J << F
missing: F