#include <iostream>
#include <fstream>
#include <vector>
#define mp make_pair
#define pb push_back
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,freq[100002],cont;
vector <int>v[100002];
void DFS(int nod)
{
    freq[nod]=1;
    for(int i=0;i<v[nod].size();i++)
    {
        if(freq[v[nod][i]]==0)
            DFS(v[nod][i]);
    }
}
int main()
{
    fin>>n>>m;
    for(int i=0;i<m;i++)
    {
        int x,y;
        fin>>x>>y;
        v[x].pb(y);
        v[y].pb(x);
    }
    for(int i=1;i<=n;i++)
    {
        if(freq[i]!=1)
        {
            DFS(i);
            cont++;
        }
    }
    fout<<cont;
    return 0;
}