#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int NMAX = 100000;

vector <int> G[NMAX + 5];

int viz[NMAX + 5];

void bfs(int start, int cc)
{
    int u;
    vector <int> :: iterator it, b, e;
    viz[start] = cc;
    queue <int> q;
    q.push(start);
    while (!q.empty())
    {
        u = q.front();
        b = G[u].begin();
        e = G[u].end();
        for (it = b; it != e; ++it)
        {
            if (!viz[*it])
            {
                viz[*it] = cc;
                q.push(*it);
            }
        }
        q.pop();
    }
}

int main()
{
    int n, m, x, y, k = 0;
    fin >> n >> m;
    for (int i = 0; i < m; ++i)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    vector <int> :: iterator it, b, e;
    for (int i = 1; i <= n; ++i)
    {
        if (!viz[i])
        {
            ++k;
            bfs(i, k);
        }
    }
    fout << k;
    return 0;
}