NYQX
      +---------
WTJMG | XWHNMRYM
       -WTJMG
        =====
        NPHZHR
       -NNVQNL
        ======
         WPJQRY
        -WPPGWL
         ======
           QXMYM
          -ZZHYL
           =====
            GGLM

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