#include<bits/stdc++.h>
using namespace std;
struct nod{
	int val;
	nod* next;
}* a[200100];
int n,m,x,y,viz[100100],ans;
void add(nod* &p, int x){
	nod* q = new nod;
	q->val=x;
	q->next = p;
	p = q; 
}
void dfs(int x)
{
	viz[x] = 1;
	for (nod* j = a[x]; j != NULL; j= j->next)
		if (!viz[j->val])
			dfs(j->val);
}
int main()
{
	ifstream cin("dfs.in");
	ofstream cout("dfs.out");
	cin >> n >> m;
	while(m--){
		cin >> x >> y;
		add(a[x],y);
		add(a[y],x);
	}
	for (int i = 1; i <= n; i++)
		if (!viz[i]){dfs(i);ans++;}
	cout << ans;
}