#include<fstream>
#include<vector>
#include<queue>
#define N 100001
using namespace std;
vector<int>G[N];
vector<int>::iterator I;
queue<int>Q;
ofstream fout("dfs.out");
int n,v[N];
void citire();
void BFS(int start);
int main()
{
	citire();
	int rez=0;
	for(int i=1;i<=n;i++)
		if(!v[i])
		{
			++rez;
			BFS(i);
		}
		fout<<rez;
		return 0;
}
void citire()
{
	ifstream fin("dfs.in");
	int m;
	fin>>n>>m;
	int i,j;
	for(;m;m--)
	{
		fin>>i>>j;
		G[i].push_back(j);
		G[j].push_back(i);
	}
}
void BFS(int start)
{
	Q.push(start);
	v[start]=1;
	while(!Q.empty())
	{
		int k=Q.front();
			
				for(I=G[k].begin();I<G[k].end();I++)
				if(!v[*I])
				{
					Q.push(*I);
					v[*I]=1;
				}
				Q.pop();
	}
}