#include <bits/stdc++.h>

using namespace std;

bitset <100001> visited;
vector <int> graph [100001];

void dfs (int node) {
    visited[node] = 1;
    for (auto x : graph[node]) {
        if (visited[x]) continue;
        dfs(x);
    }
}

int main() {
    ifstream fin ("dfs.in");
    ofstream fout ("dfs.out");
    int n, m, answer = 0;
    fin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int x, y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    for (int i = 1; i <= n; ++i) {
        if (visited[i]) continue;
        dfs (i);
        answer += 1;
    }
    fout << answer;
    return 0;
}