#include <cstdio>
#include <vector>
#include <queue>
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 ("bfs.in", "r", stdin);
    freopen ("bfs.out", "w", stdout);
    int n, m, i, x, y, nr = 0, j;
    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);
    }
    queue <int> q;
    for (i = 1; i <= n; ++i)
    {
        if (!v[i])
        {
            //addComp (i, ++nr);
            v[i] = ++nr;
            q.push(i);
            while (!q.empty())
            {
                x = q.front();
                q.pop();
                for (j = 0; j < mat[x].size(); ++j)
                {
                    if(!v[mat[x][j]])
                    {
                        v[mat[x][j]] = v[x];
                        q.push(mat[x][j]);
                    }
                }
            }
        }
    }
    printf ("%d", nr);

    return 0;
}