#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int NMAX=100004;
vector <int> L[NMAX];
bool viz[NMAX];
int n;

void citire()
{
	FILE *fin=fopen("dfs.in","r");
	int m;
	fscanf(fin,"%d%d",&n,&m);
	while (m--)
	{ int x,y;
		fscanf(fin,"%d%d",&x,&y);		
		L[x].push_back(y); 
		L[y].push_back(x);
	}
	fclose(fin);
}

void dfs(int x)
{
	queue<int> Q;
	Q.push(x); viz[x]=1;
	while (!Q.empty())
	{
		x=Q.front(); Q.pop();
		for (int i=0;i<L[x].size();++i)
		 if (!viz[L[x][i]])
			{
				Q.push(L[x][i]); viz[L[x][i]]=1;
			}
	}	
}

int main()
{
	citire();
	memset(viz,0,sizeof(viz));
	int comp=0;
	for (int i=1;i<=n;++i)
		if (!viz[i]) { ++comp; dfs(i); }
	
	FILE *fout=fopen("dfs.out","w");
	fprintf(fout,"%d\n",comp);
	fclose(fout);
	return 0;
}