#include <iostream>
#include <vector>
#include <fstream>


using namespace std;


ifstream fin("dfs.in");
ofstream fout("dfs.out");

int viz[100005];
vector <int> v[100005];

void DF(int x, int k)
{
	viz[x] = k;
	int len = v[x].size();

	for (int i = 0; i < len; ++i)
	{
		if (viz[v[x][i]] == 0) DF(v[x][i], k);
	}
}


int main()
{

	int n, m, k = 0;
	fin >> n >> m;

	//vector <int> v[100001];

	int x, y;
	for (int i = 0; i < m; ++i)
	{
		fin >> x >> y;
		v[x].push_back(y);
		v[y].push_back(x);
	}

	for (int i = 1; i <= n; ++i)
	{
		if (viz[i] == 0)
		{
			k++;
			DF(i, k);
		}
	}


	fout << k;
	return 0;
}