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

#define rep(i, n) for(int i = 0; i < 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 = 100555;
vi G[Nmax];
char vis[Nmax];

void dfs(int nod) {
  stack<int> st;
  vis[nod] = 1;
  st.push(nod);

  while(!st.empty()) {
    int x = st.top(); st.pop();
    for(auto nbr: G[x]) {
      if (!vis[nbr]) {
        vis[nbr] = 1;
        st.push(nbr);
      }
    }
  }
}

int main(void) {
  int N, M;
  fin >> N >> M;
  memset(vis, 0, N);

  int a, b;
  rep(i, M) {
    fin >> a >> b;
    --a; --b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  int answer = 0;
  rep(i, N) {
    if (!vis[i]) {
      answer++;
      dfs(i);
    }
  }
  fout << answer << endl;

  return 0;
}