#include <stdio.h>
#define N 1<<17 
#include <vector>
using namespace std;
int n,m,cont;
vector <int> v[N];
char marc[N];
void read()
{
	scanf("%d%d",&n,&m);
	int i,x,y;
	for (i=1; i<=m; i++)
	{
		scanf("%d%d",&x,&y);
		v[x].push_back(y);
		v[y].push_back(x);
	}
}
void dfs(int nod)
{
	marc[nod]=1;
	int i;
	for (i=0; i<v[nod].size(); i++)
		if (v[nod][i] && !marc[v[nod][i]])
			dfs(v[nod][i]);
}
int main()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	read();
	int i;
	for (i=1; i<=n; i++)
		if (!marc[i])
			dfs(i),cont++;
	printf("%d\n",cont);
	return 0;
}