#include <iostream>
#include <vector>
#include <fstream>
#include <queue>

using namespace std;

//DFS PE INFOARENA(teams.cere link) (parcurgere)
ifstream f("dfs.in");
ofstream g("dfs.out");
const int NMAX = 100001;
vector<int> G[NMAX];
int vis[NMAX];
void DFS(int x)
{
    //cout << x;
    vis[x] = 1;
    for (auto next : G[x]) //in loc de auto daca nu merge, bag for(int i=0;i<G[x].size();i++) int next=G[x][i];
    {
        if (!vis[next])
            DFS(next);
    }
}
int main()
{
    int n, m;
    f >> n >> m;
    for (int i = 1;i <=m;i++)
    {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    int cc = 0;
    for (int i = 1;i <= n;i++)
    {
        if (!vis[i])
        {
            cc++;
            DFS(i);
        }
    }
    g << cc;
    return 0;
}
// BFS pe infoarena (parcurgere)
/*
ifstream f("bfs.in");
ofstream g("bfs.out");
const int NMAX = 100001;
vector<int> G[NMAX];
int vis[NMAX];
int d[NMAX];
void BFS(int x)
{
    queue<int>q;
    q.push(x);
    d[x] = 0;
    vis[x] = 1;
    while (!q.empty())
    {
        x = q.front();
        //cout << x << " ";
        q.pop();
        for (auto next : G[x])
        {
            if (!vis[next])
            {
                q.push(next);
                vis[next] = 1;
                d[next] = d[x] + 1;
            }
        }
    }

}
int main()
{
    int n, m, k;
    f >> n >> m >> k;
    for (int i = 1;i <= m;i++)
    {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
    }
    BFS(k);
    for (int i = 1;i <= n;i++)
    {
        if (i != k && d[i] == 0)
        {
            g << "-1" << " ";
        }
        else
            g << d[i] << " ";
    }
    return 0;
}
*/
//
/*
int main()
{

}
*/