#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

void DFS(std::vector<std::list<int>> edges, std::vector<int> &check, int v)
{
	std::stack<int> stack_sim;

	stack_sim.push(v);
	check[v] = 1;

	while (!stack_sim.empty()) {
		int aux = stack_sim.top();
		stack_sim.pop();

		std::list<int>::iterator it;
		for (it = edges[aux].begin() ; it != edges[aux].end() ; it++) {
			if (check[*it] == 0) {
				stack_sim.push(*it);
				check[*it] = 1;
			}
		}
	}
}

int main()
{
	int V, E, i;
	int v1, v2;
	int compCon = 0;

	FILE *fd = fopen("dfs.in", "r");

	fscanf(fd, "%d", &V);
	fscanf(fd, "%d", &E);

	std::vector<std::list<int>> edges(V + 1);
	std::vector<int> check(V + 1);

	for (i = 0; i < E; i++) {
		fscanf(fd, "%d", &v1);
		fscanf(fd, "%d", &v2);

		edges[v1].push_back(v2);
		edges[v2].push_back(v1);
	}
	fclose(fd);

	for (i = 1; i < edges.size(); i++) {
		if (edges[i].size() == 0) {
			check[i] = 1;
			compCon++;
		}
	}

	for (i = 1; i < edges.size(); i++) {
		if (check[i] == 0) {
			DFS(edges, check, i);
			compCon++;
		}
	}

	FILE *fout = fopen("dfs.out", "w");
	fprintf(fout, "%d", compCon);
	fclose(fout);

	return 0;
}