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

int main() {
  int n, m;
  cin >> n >> m;

  vector<vector<int>> g(2 * n);

  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    a--; b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }

  vector<int> group(2 * n, -1);

  function<void(int, int)> dfs = [&g, &group, &dfs](int cur, int root) {
    for (int next : g[cur]) {
      if (group[next] == -1) {
	group[next] = root;
	dfs(next, root);
      }
    }
  };

  for (int i = 0; i < 2 * n; i++) {
    if (group[i] == -1) {
      group[i] = i;
      dfs(i, i);
    }
  }

  vector<int> count(2 * n, 0);
  for (int i = 0; i < 2 * n; i++) {
    count[group[i]]++;
  }
  int n_odds = 0;
  for (const int &c : count) {
    if (c & 1)
      n_odds++;
  }

  cout << n_odds / 2 << '\n';
  return 0;
}