#include <iostream>
#include <fstream>

using namespace std;

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

const int nmax = 100001;
const int mmax = 200001;
int lst[nmax], vf[2*mmax], urm[2*mmax], n, m, nr;
bool viz[nmax];

void adauga(int x, int y)
{
    ++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()
{
    int x, y, nc = 0;
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }
    for (int i = 1; i <= n; i++)
    {
        if (!viz[i])
        {
            nc++;
            dfs(i);
        }
    }
    fout << nc;
    fin.close();
    fout.close();
    return 0;
}