#include <fstream>
using namespace std;
int a[2000][2000],n,m,x,y,nc;
int v[100011];

void dfs(int nod) {
	v[nod] = 1;
	for (int i = 1;i<=n;i++)
		if (a[nod][i] == 1 && v[i] == 0)
			dfs(i);
	
}

int main() {
	ifstream fin("dfs.in");
	ofstream fout("dfs.out");
	register int i,j;
	
	fin>>n>>m;
	for (i=1;i<=m;i++) {
		fin>>x>>y;
		a[x][y] = a[y][x] = 1;
	}
	for (i=1;i<=n;i++)
		if (v[i] == 0) {
			dfs(i);
			nc++;
		}
	fout<<nc;
	return 0;
}