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

vector <int> L[100000];
int viz[100000],n,m,nr;

void ReadData()
{
	int i,x,y;
	ifstream f ("dfs.in");
	f>>n>>m;
	for (i=1;i<=m;i++)
	{
		f>>x>>y;
		L[x].push_back(y);
		L[y].push_back(x);
	}
}

void DFS(int nod)
{
	viz[nod]=1;
	for (unsigned int i=0;i < L[nod].size();i++)
	{
		int d = L[nod][i];
		if(!viz[d])
		{
			viz[d] = 1;
			DFS(d);
		}
	}
}

int main()
{
	int i;
	ReadData();
	for (i=1;i<=n;i++)
		if (viz[i]==0)
		{
			DFS(i);
			nr++;
		}
	ofstream f ("dfs.out");
	f<<nr<<"\n";
	f.close();
	return 0;
}