#3、#6AC，其余RE

#include<bits/stdc++.h>
#define ll unsigned long long
#define dep(i,a,n) for(int i = a;i >= n;i--)
#define rep(i,a,n) for(int i = a;i <= n;i++)
using namespace std;

int n,m;
int ans;
vector<vector<int>> a;
bool b[100005];

void dfs(int k){
	b[k] = true;
	rep(i,0,(int)a[k].size()-1){
		int f = a[k][i];
		if(!b[f]) dfs(f);
	}
	return ;
}


int main() {
	memset(b,false,sizeof(b));
	int x,y;
	
	cin >> n >> m;
	a.resize(n+5);
	rep(i,1,m){
		cin >> x >> y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	
//	rep(i,1,n){
//		cout << i << ":";
//		rep(j,0,a[i].size()-1){
//			cout << a[i][j] << ' ';
//		}
//		cout << endl;
//	}
//	
	rep(i,1,n){
		if(!b[i]){
		dfs(i);
			ans++;
		} 
		
	}
	cout << ans;
	return 0;
}