#include<fstream>
#include<vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
vector <int> A[100001];
int viz[100001], c[100001];
void bf(int x){//M1
	int p, u, k, i;
	p = u = 0;
	c[p] = x;
	while( p <= u ){
		k = c[p];
		p++;
		viz[k] = 1;
		for(i = 0; i < A[k].size(); i++)
			if(viz[A[k][i]] == 0){
				u++;
				c[u] = A[k][i];
			}
	}
}
/*void df( int x ){//cautare in adancime M2
	int i;
	viz[x] = 1;
	for( i = 0; i < A[x].size(); i++)
		if( viz[A[x][i]] == 0)
			df(A[x][i]);
}*/
int main(){
	int n, m, i,x,y, nr;
	f >> n >> m;
	for( i = 1; i <= m; i++ )
	{
		f >> x >> y;
		A[x].push_back(y);
		A[y].push_back(x);
	}
	nr = 0;
	for( i = 1; i <= n; i++ )
		if(viz[i] == 0){
			nr++;
			bf(i);
		}
	g << nr;
	return 0;
}