从多层树中取得偶数生成列，取得动态目标值的个数，从两个不同的树中，提取第二个树中独有的元素（和第一个树的元素不同的元素），并计算其和。-Generated columns to obtain an even number, the target value obtained from the dynamic multi-tree, from two different tree, extracts a second element that is unique in the tree (a tree of elements and different elements), and and calculate its.