#include <iostream>
#include <atcoder/dsu>
using namespace std;

int main() {
	int n, m;
	cin >> n >> m;
	atcoder::dsu uf(2 * n);
	while (m--) {
		int u, v;
		cin >> u >> v;
		u--; v--;
		uf.merge(u, v);
	}
	int ans = 0;
	for (auto i: uf.groups()) ans += i.size() % 2;
	cout << ans / 2 << '\n';
}