#include<bits/stdc++.h>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector <int > my[10000000];
int n,ans,m;bool viz[10000000];
inline void dfs(int x){
	viz[x]=1;
	for(int i(0);i<my[x].size();i++)  if (!viz[my[x][i]]) dfs(my[x][i]);
}
int main(){
	fin>>n>>m;
	for (int i(1);i<=m;i++){
		int x=0,y=0;fin>>x>>y;
		my[x].push_back(y);
		my[y].push_back(x);
		}
	for (int i(1);i<=n;i++)  if(!viz[i])  dfs(i),++ans;
    fout << ans;
	return 0;
}