#if !__INCLUDE_LEVEL__
#include __FILE__

void solve(){
    int N,M; cin>>N>>M;
    dsu UF(2*N);
    rep(i,M){
        int A,B; cin>>A>>B; A--,B--;
        UF.merge(A,B);
    }
    vector<int> P(2*N);
    rep(i,2*N)P[UF.leader(i)]++;
    int cnt=0;
    rep(i,2*N)if(P[i]%2==1)cnt++;
    cout<<cnt/2<<endl;
}

#else


#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define FOR(i,l,r) for(int i=(l);i<(r);++i)
#define rep(i,n) FOR(i,0,n)
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long,long long>;
using vi = vector<int>;
using vs = vector<string>;
using vll = vector<long long>;
#define pf push_front
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define sz(x) ((int)x.size())
#define pqueue priority_queue
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
#define INF (1<<30)-1
#define INFLL (1LL<<60)-1
#define pcnt __builtin_popcount
#define bit(n) (1LL<<(n))
#define UNIQUE(v) v.erase(unique(v.begin(),v.end()),v.end());
template<typename T> void out(T vec){for(int c:vec)cout<<c<<' ';}
void yn(bool flag){if(flag)cout<<"Yes"<<'\n'; else cout<<"No"<<'\n';}
template <typename T>
bool chmax(T &a,const T& b){if(a<b){a=b;return true;}return false;}
template <typename T>
bool chmin(T &a,const T& b){if(a>b){a=b;return true;}return false;}
void solve();

// const int mod = ;
// using mint = modint998244353;
// using mint = modint1000000007;

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    cout<<fixed<<setprecision(10);
    solve();
}

#endif