RGM
      +--------
YTUJJ | LYJXYLX
       -GLPLL
        =====
         QGJML
        -XZMQQ
         =====
         YWNZTX
        -YRHLNL
         ======
           VQGR

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: V