#include <iostream>
#include <vector>
#include <cstdio>
#include <bitset>
#define N 200005

using namespace std;

vector <int> G[N];

bitset <N> viz;

int n,m,p[N];

void dfs(int vf)
{
    viz[vf]=1;
    vector <int>::iterator it;
    for(it=G[vf].begin(); it!=G[vf].end(); ++it)
        if(!viz[*it])
            dfs(*it);
}

void citire()
{
    scanf("%d %d %d\n",&n,&m);
    for(int i=0; i<m; i++)
    {
        int x,y;
        scanf("%d %d\n",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

int main()
{
    int nr=0;
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);

    citire();

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

 cout<<nr;
    return 0;
}