#include <fstream>
#include <vector>
using namespace std;

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

const int Max = 1e6 + 1;

int n, m;
bool v[Max];

vector <int> graf[Max];

void citire()
{
    int x, y;
    fin >> n >> m;
    for (int i = 1 ; i <= m ; ++i)
    {
        fin >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
}

void dfs (int nod)
{
    v[nod] = true;
    for (int i : graf[nod])
        if (!v[i])
            dfs(i);
}

void rezolvare()
{
    int c = 0;
    for (int i = 1 ; i <= n ; ++i)
        if (!v[i])
        {
            ++c;
            dfs(i);
        }
    fout << c;
}

int main()
{
    citire();
    rezolvare();

    fin.close(); 
    fout.close();
    return 0;
}