#include<iostream>
#include<stdio.h>
#include<fstream>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
int n,nr,m,viz[100000];
vector <int>comp[100000];
vector <int>a[100001];
ifstream f("dfs.in");
ofstream g("dfs.out");
void citire()
{
    int i,k,j;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>j>>k;
        cout<<j<<" "<<k<<endl;
        a[j].push_back(k);
        a[k].push_back(j);
    }
}
void dfs(int i)
{
    viz[i]=1;
    int v,j;
    for(j=0;j<a[i].size();j++)
    {
        v=a[i][j];
        if(viz[v]==0)
        {
            viz[v]=1;
            dfs(v);
        }
    }

}
int main()
{
    citire();
    for(int i = 1; i <=n; i++)
            sort(a[i].begin(), a[i].end());

    nr=0;
    int i;
    for(i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            //comp[nr].push_back(i);
            dfs(i);
        }
    }
    g<<nr;
    return 0;
}