#include <fstream>
#include <vector>
#define dim 100001
using namespace std;

vector<int> v[dim];
bool viz[dim];


void dfs(int x){
	int i;
	viz[x]=1;	
	for(i=0;i<int(v[x].size());i++)
		if(!viz[v[x][i]]) dfs(v[x][i]);
}

int main(){
	
	int i,x,y,m,n,nr=1;
	ifstream f("dfs.in");
	ofstream g("dfs.out");

	f>>n>>m;
	for(i=1;i<=m;i++){
		f>>x>>y;
		v[x].push_back(y);
		v[y].push_back(x);		
	}

	dfs(1);
	for(i=1;i<=n;i++)
		if(!viz[i]) nr++,dfs(i);

	g<<nr;
}