#include <bits/stdc++.h>
#define ll long long
using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector<int> lista[100010];
int freq[100010];

void dfs(int start) {
    stack<int> s;
    s.push(start);

    while (!s.empty()) {
        int top = s.top();
        s.pop();

        if (!freq[top]) {
            freq[top] = 1;

            for (int i = 0; i < lista[top].size(); i++)
                    s.push(lista[top][i]);
        }
    }
}

int main() {
    int n, m;
    int x, y;

    fin >> n >> m;
    for (int i = 1; i <= m; i++) {
        fin >> x >> y;

        lista[x].push_back(y);
        lista[y].push_back(x);
    }

    int counter = 0;
    for (int i = 1; i <= n; i++) {
        if (!freq[i]) {
            dfs(i);
            counter++;
        }
    }

    /*for (int i = 1; i <= n; i++) {
        cout << "#" << i << ": ";
        for (int j = 0; j < lista[i].size(); j++)
            cout << lista[i][j] << " ";
        cout << "\n";
    }*/

    fout << counter;


    return 0;
}