ctree.p6

#!/usr/bin/env perl6
            8
          < 1 >
        0 < 1 > 1
      < 1 < 2 > 3 >
    6 < 4 < 1 > 1 > 1
  < 1 < 1 < 1 > 6 > 1 >
          1 > 1
          < 1 >
          1 < 1