????????
      +---------
TPXWP | XCHHMPPQ
       - TPXWP
        ======
         LWXCQP
        -LCRCRP
         ======
          HCWCQQ
         -HRPCNP
          ======
          ??????

base: 12
letters: CHLMNPQRTWXY
missing: Y
difficulty: hard