#include <fstream>
#include <vector>
using namespace std;

const int N=100001;
vector <int> v[N];
int n,m,nr;
bool use[N];

ifstream in("dfs.in");
ofstream out("dfs.out");

void set(int x)
{
	use[x]=true;
	for (int i=0;i<v[x].size();i++)
		if (!use[v[x][i]])
			set(v[x][i]);
}

int main()
{
	int x,y;
	in>>n>>m;
	while(m--)
	{
		in>>x>>y;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	for (int i=1;i<=n;i++)
		if (!use[i])
		{
			set(i);
			nr++;
		}
	out<<nr<<"\n";
	return 0;
}