对于一个连通图G，请采用深度优先搜索的方法，识别出该连通图的所有关节点。如下图所示。

输入：首先输入连通图G的结点个数n、边的个数m以及搜索的起始结点号，然后输入各边（u,v）；

输出：首先输出DFN和LOW数组的值，然后输出所有关节点。-For a connected graph G, use depth first search method, identify the connected graph all key points. As below.

Input: first input connected graph of the node number n G, number of the edges of the m and search the start of the node number and enter the edge (u, v)

Output: first output DFN and LOW array value, and then output all key points.