#include<fstream>
#include<vector>
#include<bitset>
#define pb push_back
using namespace std;
const int maxn=400100;

int n,m,c=0,i;
vector<int>A[maxn];
bitset<maxn>viz;

ifstream f("dfs.in");
ofstream g("dfs.out");



void citire ()
{
int x,y,i;
	f>>n>>m;
		

	for(i=1;i<=m;i++)
	{
		f>>x>>y;
	   A[x].pb(y);
	   A[y].pb(x);
	
		
	}
	f.close();
	
}

void df(int nod)
{
	int i,nr_vecini;
	viz[nod]=1;
	nr_vecini=A[nod].size();
	
	for(i=0;i<nr_vecini;i++)
		if(!viz[A[nod][i]])
			df(A[nod][i]);
		
}




int main()
{
 
  citire();
  
  for(i=1;i<=n;i++)
	  if(!viz[i])
		  {
			df(i);
			c++;  
		  }
		  
		  g<<c;
		  
		  
		  return 0;
}