#include <bits/stdc++.h>

using namespace std;
using llong = long long;
using ldbl = long double;
using lpair = pair<llong, llong>;

#define ALL(x) x.begin(), x.end()

constexpr llong mod = 1e9+7;
constexpr llong inf = mod * mod;

struct union_find {
  std::vector<int> par;

  union_find() {}
  union_find(int n) :
    par(n+1, -1)
  {}

  int root(int x) {
    if(par[x] < 0) return x;
    return par[x] = root(par[x]);
  }
  int size(int x) {
    return -par[root(x)];
  }
  bool same(int a, int b) {
    return root(a) == root(b);
  }
  bool merge(int a, int b) {
    a = root(a), b = root(b);
    if(a == b) return false;
    if(par[a] > par[b]) std::swap(a, b);
    par[a] += par[b];
    par[b] = a;
    return true;
  }
};

int main() {
  llong N, M;
  cin >> N >> M;

  union_find uf(2 * N);
  for (int i = 0; i < M; i++) {
    llong A, B;
    cin >> A >> B;
    uf.merge(A, B);
  }

  set<llong> used;
  llong cnt = 0;
  for (int i = 1; i <= 2 * N; i++) {
    if (used.count(uf.root(i))) {
      continue;
    }
    used.insert(uf.root(i));
    cnt += uf.size(i) % 2;
  }

  cout << cnt / 2 << endl;

  return 0;
}