#include <fstream>

using namespace std;

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

const int NMAX = 100001;
const int MMAX = 200001;
int lst[NMAX], vf[2 * MMAX], urm[2 * MMAX];
int n, m, nr = 0;
bool viz[NMAX];

void adauga(int x, int y)
{
    //il adauga pe y in lista de adiacenta a lui x
    ++nr;
    vf[nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int x)
{
    int p, y;
    viz[x] = true;
    for(int p = lst[x]; p; p = urm[p])
    {
        y = vf[p];
        if(!viz[y])
        {
            dfs(y);
        }
    }
}

int main()
{
    in >> n >> m;
    int x, y;
    for(int i = 0; i < m; i++)
    {
        in >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }
    int rez = 0;
    for(int i = 1; i <= n; i++)
    {
        if(!viz[i])
        {
            rez++;
            dfs(i);
        }
    }
    out << rez << '\n';
    return 0;
}