给定n个闭区间[ai, bi]（1 <= i <= n），这些区间的并可以表示为一些不相交的闭区间的并。要求在这些表示方式中找出包含不相交区间数目最少的方案。-Given n closed interval [ai, bi] (1 < = i < = n), and the interval can be expressed as a number of disjoint interval and closed. In these representations requir