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

using namespace std;

fstream fin("dfs.in");
ofstream fout("dfs.out");

int n, m;
vector<vector<int>> nodes;
vector<int> viz;
stack<int> s;
int cnt = 0;

void dfs(int x) {
  s.push(x);
  viz[x] = cnt;

  while (!s.empty()) {
    int curr = s.top();
    s.pop();
    for (auto &neigh : nodes[curr]) {
      if (!viz[neigh]) {
        dfs(neigh);
      }
    }
  }
}

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

int main() {
  fin >> n >> m;

  nodes.resize(n + 1);
  viz.resize(n + 1);

  int x, y;
  for (int i = 1; i <= n; i++) {
    fin >> x >> y;
    nodes[x].push_back(y);
    nodes[y].push_back(x);
  }

  sol();
  fout << cnt << '\n';
}