Problem Statement

You a given a undirected forest graph (see definition below) with ~n~ nodes and ~m~ edges. Determine the number of trees in the forest graph.

NOTE: A forest graph is a graph containing multiple disconnected trees. Also think twice before starting to code.

Input Format

Your first line will contain two integers ~n~ and ~m~. Your next ~m~ lines will contain two integers each, ~u~ and ~v~ denoting that ~u~ has an undirected edge to ~v~. You are guaranteed these edges will form a forest graph.

Output Format

Output a single integer, the number of trees of disconnected trees in the forest graph.

Constraints

• ~1 \leq n \leq 10^5~
• ~0 \leq m < n - 1~
• ~0 \leq u, v < n~
• You are guaranteed there are no repeated edges.
• You are guaranteed the edges will form a forest graph.

Sample Cases

Input 1

5 3
0 1
1 2
3 4

Output 1

2

Notice there are two trees in this forest, one is formed by the nodes ~\{0, 1, 2\}~ and the other by the nodes ~\{3, 4\}~.

Input 2

10 6
7 0
1 4
0 1
1 2
1 3
7 8

Output 2

4

Here we can notice that a lot of the trees are single nodes, in particular nodes ~5~, ~6~ and ~9~ have no edges and are their own trees, all other nodes form a single tree.