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

using namespace std;

ifstream fin ("dfs.in");
ofstream fout ("dfs.out");

int N, M, use[100000], k=0;
vector <int> G[100000];

void Read()
{
    fin >> N >> M;
    for (int i=1; i<=M; i++)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void DFS(int nod)
{
    use[nod]=1;
    for (int i=0; i<(int)G[nod].size(); i++)
        if (use[G[nod][i]]==0)
            DFS(G[nod][i]);
}

int main()
{
    Read();
    for (int i=1; i<=N; i++)
    {
        if (use[i]==0)
            DFS(i), k++;
    }
    fout << k;
    return 0;
}