#include <iostream>
#include <fstream>
#include <vector>
#include <deque>
#define nmx 100005
using namespace std;
int n,m,a,b,s,vf[nmx],ct;
vector <int> v[nmx];
void bfs(int source)
{
    vf[source]=1;
    deque <int> dq;
    dq.push_back(source);
    while (!dq.empty())
    {
        auto u=dq.front();
        dq.pop_front();
        for (auto it : v[u])
        {
            if (vf[it]==0)
            {
                vf[it]=1;
                dq.push_back(it);
            }
        }
    }
}
int main()
{
    ifstream f ("dfs.in");
    ofstream g ("dfs.out");
    f>>n>>m;
    for (int i=1; i<=m; i++)
    {
        f>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i=1; i<=n; i++)
        if (!vf[i])
        {
            ct++;
            bfs(i);
        }
    g<<ct;
}