articulation vertex

An articulation vertex of a graph G is a vertex whose deletion disconnects G . Let G be a graph with n vertices and m edges. Give a simple O(n+m) algorithm for finding a vertex of G that is not an articulation vertex i.e. whose deletion does not disconnects G.

Q-> Following up on the previous problem, give a O(n+m) algorithm that finds a deletion order for the n vertices such that no deletion disconnects the graph