#include<fstream>
#include<vector>
using namespace std;
#define NMAX 100010
ifstream f("dfs.in");
ofstream g("dfs.out");
vector<int> a[NMAX];
int n,m,viz[NMAX],nc;
void cit()
{
	f>>n>>m;
	for(int i=1;i<=m;i++)
	{
		int x,y;
		f>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
}
void dfs(int x)
{
	viz[x]=1;
	vector <int>::iterator it;
	for(it=a[x].begin();it!=a[x].end();++it)
		if(!viz[*it])
			dfs(*it);
}
int main()
{
	cit();
	for(int i=1;i<=n;++i)
		if(!viz[i])
			{
				nc++;
				dfs(i);
		}
	g<<nc;
	return 0;
}