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

int n,m,s,ap[100100];
queue<int> Q;
vector<int> A[100100];

int main()
{
	ifstream in("bfs.in");
	ofstream out("bfs.out");
	
	in>>n>>m;
	for(int i=1;i<=m;++i)
	{
		int x,y;
		in>>x>>y;
		A[x].push_back(y);
		A[y].push_back(x);
	}
	
	int sol=0;
	for(int i=1;i<=n;++i)
	{
		if(!ap[i])
		{
			++sol;
			ap[i]=1;
			Q.push(i);
			for(;!Q.empty();Q.pop())
			{
				int ret=Q.front();
				for(vector<int>::iterator it=A[ret].begin();it!=A[ret].end();++it)
				{
					if(!ap[*it])
					{
						ap[*it]=1;
						Q.push(*it);
					}
				}
			}
		}
	}
	
	out<<sol<<'\n';
	
	out.close();
	return 0;
}