Problems
Number of hanging vertices 2
Number of hanging vertices 2
Given a simple undirected unweighted graph. Count the number of hanging vertices in it. The vertex is hanging, if its degree is 1.
Input
The first line contains two numbers n and m (1 ≤ n, m ≤ 1000) - the number of vertices and the number of edges. Next m lines contain a list of edges.
Output
Print the number of hanging vertices in a graph.
Input example #1
2 1 1 2
Output example #1
2
Input example #2
3 3 1 2 1 3 2 3
Output example #2
0