#include<stdio.h>
#include<vector>

using namespace std;

#define pb push_back
#define lg 100005

int n, m, x, y, nr[lg], fst[lg], nrc, i;
vector <int> v[lg];

void df(int nod){
	int i;

	fst[nod] = 1;
	for (i = 0; i < nr[nod]; i ++)
		if (!fst[v[nod][i]])
			df(v[nod][i]);
}

int main()
{
	freopen("dfs.in", "rt", stdin);
	freopen("dfs.out", "wt", stdout);

	scanf("%d%d", &n, &m);
	for (i = 1; i <= m; i ++){
		scanf("%d%d", &x, &y);

		nr[x] ++;
		v[x].pb(y);

		nr[y] ++;
		v[y].pb(x);
	}

	for (i = 1; i <= n; i ++)
		if (!fst[i]){
			nrc ++;
			df(i);
		}

	printf("%d\n", nrc);

	return 0;
}