#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
#define repn(i,end) for(long long i = 0; i <= (long long)(end); i++)
#define reps(i,start,end) for(long long i = start; i < (long long)(end); i++)
#define repsn(i,start,end) for(long long i = start; i <= (long long)(end); i++)
#define ll long long
#define ld long double
#define print(t) cout << t << endl 
#define all(a)  (a).begin(),(a).end()
// << std::fixed << std::setprecision(0)
const ll INF = 1LL << 60;
 
template<class T> bool chmin(T& a, T b){
 if(a > b){
  a = b;
  return true;
 }
  return false;
}
 
template<class T> bool chmax(T& a, T b){
 if(a < b){
  a = b;
  return true;
 }
  return false;
}
  
ll lpow(ll x,ll n){
  ll ans = 1;
  while(n >0){
    if(n & 1)ans *= x;
    x *= x;
    n >>= 1;
  }
  return ans;
}
 
int main(){
  ll n,m;cin >> n >> m;
  dsu uf(2 * n);
  rep(i,m){
    ll a,b;cin >> a >> b;
    a--;b--;
    uf.merge(a,b);
  }
  vector<vector<int>> gru = uf.groups();
  ll ans = 0;
  rep(i,gru.size()){
    if(gru[i].size() %2 != 0){
      ans++;
    }
  }
  cout << ans/2 << endl;
}