#include<bits/stdc++.h>
#define ll long long
#define For(i,a,n) for(int i=a;i<=n;i++)
#define rep(i,b,x) for(int i=b;i>=x;i--)
using namespace std;
vector< vector<int> >a;
bool f[200005];
int n,m;
int x,y;
int ans;
void dfs(int k) {
	f[k]=1;
	For(i,0,a[k].size()-1) {
		if(!f[a[k][i]]) {
			dfs(a[k][i]);
		}
	}
	return ;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	a.resize(n+1);
	For(i,1,m) {
		cin>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);

	}
	For(i,1,n) {
		if(!f[i]) {
			ans++;
			dfs(i);
		}
	}
	cout<<ans;
	return 0;
}