XYU
      +--------
QJNRM | PTTJUWL
       -PRXYF
        =====
         WJHUW
        -UWPLF
         =====
          MQJWL
         -WHMXM
          =====
          QJUTX

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
missing: G