#include <bits/stdc++.h>
using namespace std;
// #include <atcoder/all>
// #include <atcoder/modint>
// #include <atcoder/segtree>
// #include <atcoder/lazysegtree>
#include <atcoder/dsu>
// #include <atcoder/scc>
using namespace atcoder;

// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

typedef long long int ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<vvll> vvvll;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef priority_queue<pll, vpll, function<bool(pll,pll)> > pqpll; 
typedef priority_queue<ll, vll, function<bool(pll,pll)> > pqll;
 
struct edge{ ll to, cost; edge(ll e_to,ll e_cost): to(e_to), cost(e_cost){} };
typedef vector<vector<edge>> Graph;
 
#define rep(i,a,n) for(ll i = a;i < n;i++)
#define rrep(i,a,n) for(ll i = n-1; i >= a;i--)
#define LINF (1LL << 60)
#define INF (1 << 30)
#define fs first
#define sc second
#define EPS (ld)1e-10
#define ALL(a) a.begin(), a.end()
#define tcheck(a) if((clock() - start)/(ld)CLOCKS_PER_SEC >= a) break
#define debug(s) cout << #s << endl
#define debugval(x) cout << #x" = " << x << endl
 
template<typename T> ll sz(vector<T> &pos){ return (ll)pos.size(); }
template<typename T> ll sz(priority_queue<T, vector<T> > &que) {return (ll)que.size(); }
template<typename T> ll sz(priority_queue<T, vector<T>, greater<T> > &que) {return (ll)que.size(); }
ll sz(string &s) {return (ll)s.size(); } 
 
template<typename T> void chmin(T &a, T b) { if(a > b) a = b; }
template<typename T> void chmax(T &a, T b) { if(a < b) a = b; }
 
ll gcd(ll a,ll b){ return ((!b) ?a :gcd(b, a%b)); }
ll lcm(ll a,ll b){ return a / gcd(a,b) * b; }
// ll dx[4] = {0,-1,0,1},dy[4] = {-1,0,1,0};
ll dx[8] = {0,-1,-1,-1,0,1,1,1},dy[8] = {-1,-1,0,1,1,1,0,-1};
inline bool isinside(ll i,ll n){ return (i < n && i >= 0); }

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

    dsu uf(2*n);
    rep(i,0,m){
        ll u,v; cin >> u >> v;
        u--; v--;
        uf.merge(u,v);
    }

    ll ans = 0;
    rep(i,0,2*n){
        if(uf.leader(i) == i){
            ans += uf.size(i) % 2;
        }
    }
    ans /= 2;

    cout << ans << endl;
}