#include <vector>
#include <fstream>
#include <iostream>
 
using namespace std;
 
int n,m,sol;
vector<int> a[100003];
bool viz[100003];
 
inline void Citire()
{
    int i,x,y;
    ifstream fin("dfs.in");
    fin>>n>>m;
    for(i=1;i<=m;++i)
    {
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}
 
inline void Cauta(int k)
{
    int i;
    for(i=0;i<a[k].size();++i)
        if(viz[a[k][i]]==false)
        {
		viz[a[k][i]]=true;
		Cauta(a[k][i]);
	   }
}
 
int main()
{
    int i;
    Citire();
    for(i=1;i<=n;++i)
    {
        if(viz[i]==false)
        {
            sol++;
		 viz[i] = true;
            Cauta(i);
        }
    }
    ofstream fout("dfs.out");
    fout<<sol<<"\n";
    fout.close();
    return 0;
}