#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

int N,M;
vector<int> G[100001];
int Use[100001];

void Read()
{
	fin>>N>>M;

	for(int i=1;i<=M;i++)
	{
        int x,y;

		fin>>x>>y;

		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void DFS(int nod)
{
	Use[nod] = 1;

	for(int i=0;i<G[nod].size();i++)
	{
		int vecin = G[nod][i];
		if (Use[vecin] == 0){
            DFS(vecin);
		}
	}
}

int main()
{
	Read();
	int c = 0;
	for(int i=1;i<=N;i++)
	{
		if (Use[i] == 0){
			c++;
			DFS(i);
		}
	}
	fout<<c;
	return 0;
}