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

using namespace std;

bool dfs_recursive(
    int n,
    vector<int>& cycle,
    vector<int>& seen,
    vector<int>& visiting,
    const vector<vector<int>>& edges)
{
  visiting[n] = 1;
  seen[n] = 1;
  for (auto e : edges[n]) {
    if (visiting[e] == 1) {
      cycle.push_back(e);
      return true;
    }
    if (!seen[e]) {
      bool c = dfs_recursive(e, cycle, seen, visiting, edges);
      visiting[e] = 0;
      if (c) {
        if (cycle[0] == e)
          return false;
        cycle.push_back(e);
        return true;
      }
    }
  }
  return false;
}

bool dfs_iterative(
    int n,
    vector<int>& cycle,
    vector<int>& seen,
    vector<int>& visiting,
    const vector<vector<int>>& edges)
{
  // i is source
  stack<int> fringe;
  fringe.push(n);
  while (!fringe.empty()) {
    int next = fringe.top();
    fringe.pop();

    if (seen[next])
      continue;
    seen[next] = 1;
    visiting[next] = 0;

    for (auto e : edges[next]) {
      if (!seen[e]) {
        visiting[e] = 1;
        fringe.push(e);
      }
    }
  }
}

int main() {
  ifstream f{"dfs.in"};
  ofstream g{"dfs.out"};

  int n, m;
  f >> n >> m;

  vector<vector<int>> edges(n);
  for (int i = 0; i < m; i++) {
    int s, d;
    f >> s >> d;
    s--; d--;
    edges[s].push_back(d);
    edges[d].push_back(s);
  }

  vector<int> seen(n, 0), visiting(n, 0);
  int i = 0;
  int comps = 0;
  while (i < seen.size()) {
    while (i < seen.size() && seen[i] == 1)
      i++;
    if (i == seen.size())
      break;

    // i is source
    vector<int> cycle;
    //dfs_iterative(i, cycle, seen, visiting, edges);
    dfs_recursive(i, cycle, seen, visiting, edges);
    //if (cycle.size() > 0) {
      //std::cout << "Found cycle = ";
      //for (auto nn : cycle) {
        //std::cout << nn << " ";
      //}
      //std::cout << std::endl;
    //}
    comps++;
  }
  g << comps << endl;
}