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

int v[100001];
vector <int> mat[100001];

void addComp (int x, int nr)
{
    v[x] = nr;
    int i, n = mat[x].size();
    for (i = 0; i < n; ++i)
    {
        if (!v[mat[x][i]])
        {
            addComp (mat[x][i], nr);
        }
    }
}

int main()
{
    freopen ("dfs.in", "r", stdin);
    freopen ("dfs.out", "w", stdout);
    int n, m, i, x, y, nr = 0;;
    scanf ("%d%d", &n, &m);
    for (i = 0; i < m; ++i)
    {
        scanf ("%d%d", &x, &y);
        mat[x].push_back(y);
        mat[y].push_back(x);
    }
    for (i = 1; i <= n; ++i)
    {
        if (!v[i])
        {
            addComp (i, ++nr);
        }
    }
    printf ("%d", nr);

    return 0;
}