#include <stdio.h>
#include <vector>
#include <list>
using namespace std;

int n, m, nr_c = 0;
vector< list<int> > vecini;
vector<bool> sel;

void read();
void solve();
void write();
void dfs(int);

int main()
{
	read();
	solve();
	write();
	return 0;
}

void dfs(int p)
{
	sel[p] = 1;
	list<int>::iterator i, sfarsit = vecini[p].end();
	for (i = vecini[p].begin(); i != sfarsit; ++i)
	{
		if (!sel[*i])
		{
			dfs(*i);
		}
	}
}

void solve()
{
	int i;
	for (i = 1; i <= n; ++i)
	{
		if (!sel[i])
		{
			++nr_c;
			dfs(i);
		}
	}
}

void write()
{
	FILE *fout = fopen("dfs.out", "w");
	fprintf(fout, "%d\n", nr_c);
	fclose(fout);
}

void read()
{
	int i, x, y;
	FILE *fin = fopen("dfs.in", "r");
	fscanf(fin, "%d%d", &n, &m);
	vecini.resize(n + 1);
	for (i = 1; i <= m; ++i)
	{
		fscanf(fin, "%d%d", &x, &y);
		vecini[x].push_back(y);
		vecini[y].push_back(x);
	}
	fclose(fin);
	sel.resize(n + 1, 0);
}