#include<fstream>
#include<vector>
#define dim 200007

using namespace std;


ifstream f("dfs.in");
ofstream g("dfs.out");
vector< int >G[dim];
int n,m,x,y,i,nr;
int viz[dim];

void dfs(int nod) {
	viz[nod]=1;
	for(int i=0;i<G[nod].size();++i){
		if(!viz[G[nod][i]])
			dfs(G[nod][i]);
		
	}
}
int main () {
	
	f>>n>>m;
	
	for(i=1;i<=n;++i){
		f>>x>>y;
		
		G[x].push_back(y);
		G[y].push_back(x);
		
	}
	
	for(i=1;i<=n;++i){
		if(!viz[i]){
			dfs(i);
			++nr;
		}
	}
	g<<nr<<"\n";
	return 0;
}