TTNF
      +---------
CFRYR | URJJFRCN
       -CFRYR
        =====
        TTUJUR
       - CFRYR
        ======
         RNUYHC
        -RQJGGF
         ======
          TNFRNN
         -TQRUUC
          ======
            CQGU

base: 11
letters: CFGHJNQRTUY
difficulty: intermediate
restrictions: no multiplication