JLRP
      +---------
GTGNL | HXGNPQNT
       -NNJMR
        =====
        GYRFYQ
       -GMMJFG
        ======
         GPMRHN
        -GQRGPJ
         ======
           TWRGT
          -TTMYT
           =====
            JQYU

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