#include <bits/stdc++.h>
int n, m, viz[100005], cnt;
ifstream fin ("dfs.in"); ofstream fout ("dfs.out");
typedef struct nod
{
	int x;
	nod *a;
} *pNod;
pNod v[100005];
 
void add(pNod &dest, int val)
{
	pNod p;
	p = new nod;
	p -> x = val;
	p -> a = dest;
	dest = p;
}
 
void citire()
{
	fin>> n >> m;
	int i, x, y;
	for (i = 1; i <= m; i++)
	{
		fin >> x >> y;
		add(v[x], y);
		add(v[y], x);
	}
}
 
void DFS(int nod)
{
	pNod p;
	viz[nod] = 1;
	for (p = v[nod]; p != NULL; p = p -> a) if (!viz[p -> x]) DFS(p -> x);
}	
 
int main()
{
	citire();
	int i;
	for (i = 1; i <= n; i++) if (!viz[i]) { cnt++; DFS(i);}
	fout << cnt << '\n';
	return 0;
}