CYCC
      +---------
MHRTC | RFNHYCMM
       -RFHHC
        =====
          RNCCM
         -RFHHC
          =====
           RFHRM
          -RFHHC
           =====
              FR

base: 10
letters: CEFHMNRTUY
hints: U << E
difficulty: hard
missing: E U