What if we have a three-level hierarchy and need to enumerate only "B"s (according to the pattern), but some "C-"s interfere with "B"s.What if we have a three-level hierarchy and nee
What if we have a three-level hierarchy and need to enumerate only "B"s (according to the pattern), but some "C-"s interfere with "B"s.What if we have a three-level hierarchy and nee