using namespace std;
#include<cstdio>
#include<vector>
#define NMAX 100005
vector <int> G[NMAX];
bool viz[NMAX];
int n,m,contor;
void citire()
{
	freopen("dfs.in","r",stdin);
	scanf("%d %d",&n,&m);
	int x,y,i;
	for(i=1;i<=m;i++)
	{
		scanf("%d %d",&x,&y);
		G[(unsigned)x].push_back(y);
		G[(unsigned)y].push_back(x);
	}
}
void DFS(int nod)
{
	viz[nod]=1;
	for(unsigned i=0;i<G[nod].size();i++)
		if(!viz[G[nod][i]])
			DFS(G[nod][i]);
}
void BVO()
{
	for(int i=1;i<=n;i++)
		if(!viz[i])
		{
			DFS(i);
			contor++;
		}
}
void afisare()
{
	freopen("dfs.out","w",stdout);
	printf("%d\n",contor);
}
int main()
{
	citire();
	BVO();
	afisare();
	return 0;
}