You are to write a program that receives a connected undirected graph and finds
all its articulation points, which are the vertices that, if removed,
leave disconnected graph.
Input file format
Input file contains two integers N and M.
Vertices are numbered with integer numbers from 1 to N.
M is the number of edges.
Each of next M lines contain pair of integers — numbers of vertices
connected by an edge. There are no pairs of equal numbers.
Output file format
Output file must contain integer representing a quantity of articulation
points, followed by numbers of corresponding vertices in arbitrary order.
