#include<fstream>
#include<vector>
#include<cstring>
using namespace std;
int k,viz[100005],n;
vector<int>a[100005];
void dfs(int x)
{
  int m,i;
	viz[x]=1;
	m=a[x].size();
	for(i=0;i<=m-1;i++)
  if(!viz[a[x][i]]) dfs(a[x][i]);
}
int main()
{

int m,i,x,y;
	ifstream fi("dfs.in");
	ofstream fo("dfs.out");
	fi>>n>>m;
	for(i=1;i<=m;i++)
	{
		fi>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);


	}
	k=0;
	memset(viz,0,sizeof(viz));
	for(i=1;i<=n;i++) if(!viz[i]) {k++; dfs(i); }
	fo<<k<<"\n";
	fo.close();

}