????????
      +---------
UUELM | XMNNPUML
       -JPGCMM
        ======
         NUJPUM
        -NGXUXM
         ======
           CNJML
          -UUELM
           =====
           ?????

base: 12
letters: CEGJLMNPRUXY
missing: Y R
hints: U << Y
difficulty: hard