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

vector< vector<int> > a;
bool s[100001];
int n, m;
int nr;

void Read();
void BFS(int );
void Write();

int main()
{
	Read();
	for(int i = 1; i <= n; ++i)
		if(!s[i]) 
		{
			++nr;
			BFS(i);
		}
	Write();
}

void Read()
{
	ifstream fin("dfs.in");
	fin >> n >> m;
	a.resize(n+1);
	
	int x, y;
	for(int i = 1; i <= m; ++i)
	{
		fin >> x >> y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	fin.close();
}

void DFS(int nod)
{
	s[nod] = 1;
	for(int i = 0; i < (int)a[nod].size(); ++i)
	{
		int y = a[nod][i];
		if(s[y] == 0)
			s[y] = 1;
		
		DFS(y);
	}
}

void Write()
{
	ofstream fout("dfs.out");
	fout << nr;
	fout.close();
}