#include <bits/stdc++.h>

#define NMAX (int)1e5 + 5

using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

vector<int> adj[NMAX];
bool visited[NMAX];
int N, M, node, neigh;

void DFS(int current_node) {
	visited[current_node] = true;
	
	if (adj[current_node].size() == 0)
		return;
	
	for (int i = 0; i < adj[current_node].size(); i++) {
		if (visited[adj[current_node][i]] == false)
			DFS(adj[current_node][i]);
	}
}

int main(void) {
	f >> N >> M;

	for (int i = 1; i <= M; i++) {
		f >> node >> neigh;
		adj[node].push_back(neigh);
		adj[neigh].push_back(node);
	}

	int counter = 0;

	for (int i = 1; i <= N; i++) {
		if (visited[i] == false) {
			counter++;
			DFS(i);
		}
	}

	g << counter;
}