Problem Statement

You are given a simple undirected graph with N vertices numbered 1 to N and M edges numbered 1 to M. Edge i connects vertex u_i and vertex v_i.
Find the number of connected components in this graph.

Input

The input is given from Standard Input in the following format:
N M
u_1 v_1
u_2 v_2
$\vdots$
u_M v_M

Output

Print the answer.

Constraints

• $1 \leq N \leq 100$
• $0 \leq M \leq \frac{N(N - 1)}{2}$
• $1 \leq u_i, v_i \leq N$
• The given graph is simple.
• All values in the input are integers.

Sample Input 1

5 3
1 2
1 3
4 5

Sample Output 1

2

The given graph contains the following two connected components:

• a subgraph formed from vertices 1, 2, 3, and edges 1, 2;
• a subgraph formed from vertices 4, 5, and edge 3.

Sample Input 2

5 0

Sample Output 2

5

Sample Input 3

4 6
1 2
1 3
1 4
2 3
2 4
3 4

Sample Output 3

1

见题面 Input 部分

见题面 Output 部分