#include <iostream>
#include <vector>
#include <map>

using namespace std;
/*
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
*/
#define all(x) (x).begin(),(x).end()
#define rep(i, n) for (int i = 0; i < (n); i++)
#define endl "\n"

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {os << "["; for (const auto &v : vec) {os << v << ","; } os << "]"; return os;}
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &p) {os << "(" << p.first << ", " << p.second << ")"; return os;}
ll mod_pow(ll a, ll n, ll mod) { ll ret = 1; ll p = a % mod; while (n) { if (n & 1) ret = ret * p % mod; p = p * p % mod; n >>= 1; } return ret; }

const int mod = 1e9 + 7;
struct UnionFind {
    vector<int> data;
    int gnum;
    UnionFind(int size) : data(size, -1), gnum(size) {}
    bool unionSet(int x, int y) {
        x = root(x); y = root(y);
        if (x != y) {
            if (data[y] < data[x]) swap(x, y);
            data[x] += data[y]; data[y] = x;
            gnum--;
        }
        return x != y;
    }
    bool findSet(int x, int y) {
        return root(x) == root(y);
    }
    int root(int x) {
        return data[x] < 0 ? x : data[x] = root(data[x]);
    }
    int size(int x) {
        return -data[root(x)];
    }
    int getGroupNum() {
        return gnum;
    }
    vector<vector<int>> getGroups() {
        map<int, vector<int>> G;
        int N = data.size();
        for (int i = 0; i < N; i++) {
            G[root(i)].push_back(i);
        }
        vector<vector<int>> ret;
        for(auto g : G) {
            ret.push_back(g.second);
        }
        return ret;
    }
};

void solve() {
    int N, M; cin >> N >> M; N *= 2;
    UnionFind uf(N);

    for (int i = 0; i < M; i++) {
        int a, b; cin >> a >> b; a--, b--;
        uf.unionSet(a, b);   
    }

    vector<vector<int>> G = uf.getGroups();
    int cnt = 0;
    for (int i = 0; i < G.size(); i++) {
        if (G[i].size() % 2 == 1) cnt++;
    }

    cout << cnt / 2 << endl;
}

int main() {
    #ifdef LOCAL_ENV
    cin.exceptions(ios::failbit);
    #endif
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout.setf(ios::fixed);
    cout.precision(16);
    
    solve();
}