#include <stdio.h>
#include <bits/stdc++.h>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
// const int INF = 0x3f3f3f3f;

ifstream fin {"dfs.in"};
ofstream fout {"dfs.out"};

const int Nmax = 100'005;
vi G[Nmax];
char vis[Nmax];

int main(void) {
  // freopen("dfs.in", "r", stdin);
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);

  memset(vis, 0, sizeof(vis));
  int N, M, a, b;
  fin >> N >> M;
  rep(i, M) {
    fin >> a >> b;
    --a, --b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  queue<int> Q;
  int ans = 0;
  rep(i, N) {
    if (vis[i]) continue;
    ans++;
    Q.push(i); vis[i] = 1;
    while(!Q.empty()) {
      auto x = Q.front(); Q.pop();
      for(auto y: G[x]) {
        if (!vis[y]) {
          vis[y] = 1;
          Q.push(y);
        }
      }
    }
  }
  fout << ans << '\n';

  return 0;
}