#include <iostream>
#include <fstream>
#include <vector>
#include <stack>

using namespace std;

int visited[100005];
vector <int> v[100005];
long long n, m, x, y, cnt, tst;

void dfsRec(int node) {
    visited[node] = 1;
    for (long long i = 0; i < v[node].size(); i++) {
        if (visited[v[node][i]] == 0)
            dfsRec(v[node][i]);
    }

}

void dfsIter(int node) {
    stack <int> s;
    s.push(node);
    while (!s.empty()) {
        node = s.top();
        s.pop();
        if (!visited[node]) {
            visited[node] = 1;
            for (int i = 0; i < v[node].size(); i++)
                s.push(v[node][i]);
        }
    }
}

int main()
{
    ifstream f("dfs.in");
    ofstream g("dfs.out");

    f >> n >> m;
    for (long long i = 0; i < m; i++) {
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (long long i = 1; i <= n; i++)
        if (!visited[i]) {
            cnt++;
            dfsIter(i);
        }
    g << cnt;

    f.close();
    g.close();
    return 0;
}