#ifdef SENJAN
#define _GLIBCXX_DEBUG
#else
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#endif
#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using namespace atcoder;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
using bint = boost::multiprecision::cpp_int;
using graph=vector<vector<int>>;
template<class T> using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
constexpr int INF32=INT_MAX/2;
constexpr ll INF64=LLONG_MAX/2;
constexpr ld PI=3.14159265358979323846;
constexpr int dx[]={0,0,-1,1,-1,-1,1,1},dy[]={-1,1,0,0,-1,1,-1,1};
template<class T> inline bool chmax(T &a,T b){return a<b?a=b,true:false;}
template<class T> inline bool chmin(T &a,T b){return a>b?a=b,true:false;}
inline void dispYN(bool a){cout<<(a?"YES":"NO")<<endl;}
inline void dispYn(bool a){cout<<(a?"Yes":"No")<<endl;}
inline void dispyn(bool a){cout<<(a?"yes":"no")<<endl;}
void _main();
int main(){cin.tie(0)->sync_with_stdio(0);cout<<fixed<<setprecision(16);_main();}

void _main(){
  int n, m; cin >> n >> m;
  dsu uf(2*n);
  for(int i=0; i<m; i++){
    int a, b; cin >> a >> b;
    a--, b--;
    uf.merge(a, b);
  }

  auto gr = uf.groups();
  int ans = 0;
  for(const auto &g:gr){
    if(g.size()%2==1){
      ans++;
    }
  }
  cout << ans/2 << endl;
}