#include<fstream>
#include<vector>

using namespace std;

vector<int> a[100001];
int viz[100001];
int n,m,i,j,x,y,nrcc;

void dfs(int x)
{
	viz[x]=1;
	vector<int>::iterator it;
	for (it=a[x].begin();it<a[x].end();++it)
	if (viz[*it]==0) dfs(*it);
}
	
int main(){
	
	ifstream f("dfs.in");
	ofstream g("dfs.out");
	
	f>>n>>m;
	
	for (i=0;i<n;++i)
	{
		f>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	nrcc=0;
	for (i=1;i<=n;i++)
		if(viz[i]==0)
		{
			nrcc++;
			dfs(i);
		}
	g<<nrcc<<"\n";
	f.close();
	g.close();
	return 0;
}