WJMM
      +---------
NHTNP | HQLQHZRL
       -NHTNP
        =====
        XUJZPZ
       -XMGTMN
        ======
         GXLLGR
        -GWQRWV
         ======
          GGRTTL
         -GWQRWV
          ======
           TQMYP

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: challenging
hints: Q << R, T << L, L << V
missing: Y