4216
      +---------
316C3 | 6538D9CA
       -67155
        =====
         442E9
        -316C3
         =====
         39254C
        -374B9B
         ======
          38016A
         -352CCD
          ======
            674C

base: 15
letters: 0123456789ABCDE
difficulty: medium