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

using namespace std;

vector <int> G[100010];
bool viz[100010];
int N, M;
int rez;

void Read()
{
    ifstream f("dfs.in");
    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);
    }
    f.close();
}

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

void Solve()
{
    for (int i = 1; i <= N; ++ i)
    {
        if(!viz[i])
        {
            rez++;
            DFS(i);
        }
    }
}

void Write()
{
    ofstream g("dfs.out");
    g << rez << "\n";
    g.close();
}

int main()
{
    Read();
    Solve();
    Write();
    return 0;
}