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

using namespace std;

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

const int NMAX = 100'001;

int N, M;
vector < int > G[NMAX];
bitset < NMAX > vis;

void dfs(const int& startNode) {

    stack < int > s;

    vis[startNode] = 1;
    s.push(startNode);

    while(!s.empty()) {

        const int node = s.top();
        s.pop();

        for(const int& neighbor : G[node]) {
            if(!vis[neighbor]) {
                vis[neighbor] = 1;
                s.push(neighbor);
            }
        }
    }
}

int main() {

    f >> N >> M;

    for(int i = 1;i <= M;++i) {
        int x, y;
        f >> x >> y;

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

    int cnt{};
    for(int i = 1;i <= N;++i) {
        if(!vis[i]) {
            dfs(i);
            cnt++;
        }
    }

    g << cnt;

    return 0;
}