neps309.cpp

/*
 * Contest : Neps
 * Problem : 309 - Gincana (OBI 2011)
 * Link    : https://neps.academy/br/exercise/309
 */

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

#define fastio ios::sync_with_stdio(0); cin.tie(0);

vector<vector<int>> adj;
vector<int> visited;

void dfs(int no) {
  visited[no] = true;

  for (auto &v : adj[no])
    if (!visited[v]) dfs(v);
}

int main() {
  fastio

  int n, m, a, b, cnt = 0;
  cin >> n >> m;

  adj.assign(n + 1, vector<int>());
  visited.assign(n + 1, false);

  while (m--) {
    cin >> a >> b;

    adj[a].push_back(b);
    adj[b].push_back(a);
  }

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

  cout << cnt << '\n';

  return 0;
}