Number of Connected Components

A graph has n nodes numbered 0 to n - 1 and some undirected edges. Return the number of connected components: groups of nodes that can reach each other.

For n = 5 and edges = [[0, 1], [1, 2], [3, 4]] the answer is 2.

Examples

Example 1

Input:

count_components(5, [[0, 1], [1, 2], [3, 4]])

Output:

2

Example 2

Input:

count_components(3, [])

Output:

3

Constraints

• 0 <= n <= 100000
• 0 <= len(edges) <= 200000
• 0 <= a, b < n; there may be repeated edges.