FNM
      +--------
RRUWU | FJJXUJL
       -FFYRL
        =====
         NXLYJ
        -NUPLQ
         =====
          JLPWL
         -MJYXW
          =====
          RRNXR

base: 13
letters: FGJLMNPQRUWXY
difficulty: hard
missing: G