#include <fstream>

using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");
const int NMAX = 100001;
const int MMAX = 200001;

int lst[NMAX], vf[2 * MMAX], urm[2 * MMAX], viz[NMAX];
int n, m, nr;

void adauga(int, int);
void dfs(int);
int main()
{
    cin >> n >> m;
    for(int i = 1; i <= m; ++i)
    {
        int x, y;
        cin >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }

    int tot = 0;
    for(int i = 1; i <= n; ++i)
    {
        if(!viz[i])
        {
            tot++;
            dfs(i);
        }
    }
    cout << tot << '\n';
    return 0;
}

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] = 1;
    p = lst[x];
    while(p)
    {
        y = vf[p];
        if(!viz[y])
            dfs(y);
        p = urm[p];
    }
}