#include <bits/stdc++.h>
using namespace std;
#define overload4(_1, _2, _3, _4, name, ...) name
#define rep1(n) for(int i = 0; i < (int)(n); ++i)
#define rep2(i, n) for(int i = 0; i < (int)(n); ++i)
#define rep3(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep4(i, a, b, c) for(int i = (a); i < (int)(b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using u16 = uint16_t;
int main(){
	int N,M;
	cin >> N >> M;
	vector<vector<int>> graph(2*N);
	rep(i,M){
		int a,b;
		cin >> a >> b;
		--a;--b;
		graph.at(a).push_back(b);
		graph.at(b).push_back(a);
	}
	vector<int> ccid(2*N, -1);
	int ccn = 0;
	auto dfs = [&](auto f, int v)->void{
		if(ccid.at(v) != -1)return;
		ccid.at(v) = ccn;
		for(auto nv : graph.at(v)){
			f(f, nv);
		}
	};
	rep(i,2*N){
		if(ccid[i] != -1)continue;
		dfs(dfs, i);
		ccn++;
	}
	vector<int> groupSize(2*N,0);
	rep(i,2*N){
		groupSize.at(ccid.at(i))++;
	}
	int ans = 0;
	rep(i,2*N){
		if(groupSize.at(i) % 2 == 1)ans++;
	}
	cout << ans/2 << endl;
}