#include <iostream>
#include <cassert>
#include <map>
#include <vector>
using namespace std;

struct UnionFind
{
    vector<int> data;
    const uint __size;
    UnionFind(const int size = 0) noexcept : data(size, -1), __size(max(0, size)) {}
    inline int root(const int& x) {
        if (data[x] < 0) return x;
        return data[x] = root(data[x]);
    }
    inline bool unite(const int& x, const int& y) {
        int rx = root(x), ry = root(y);
        if (rx == ry) return false;
        if (data[rx] > data[ry]) swap(rx, ry);
        data[rx] += data[ry];
        data[ry] = rx;
        return true;
    }
    inline bool same(const int& x, const int& y) { return root(x) == root(y); }
    inline int size(const int& x) { return -data[root(x)]; }
};

int main() {
    int n, m;
    cin >> n >> m;
    assert(1 <= n && n <= 100000);
    assert(0 <= m && m <= 100000);
    UnionFind uf(2 * n);

    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        assert(1 <= a && a <= 2 * n);
        assert(1 <= b && b <= 2 * n);
        uf.unite(a, b);
    }

    int ans = 0;
    for (int i = 1; i <= 2 * n; ++i) {
        if (uf.root(i) == i && uf.size(i) % 2) {
             ans += 1;
        }
    }
    cout << ans / 2 << endl;
    return 0;
}