#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001



int main(){
	
	int n,m;
	cin>>n>>m;
	
	dsu D(n*2);
	vector<int> a(m),b(m);
	rep(i,m){
		cin>>a[i]>>b[i];
		a[i]--,b[i]--;
	}
	
	rep(i,m){
		D.merge(a[i],b[i]);
	}
	int ans = 0;
	rep(i,n*2){
		if(D.leader(i)==i){
			ans += D.size(i)%2;
		}
	}
	cout<<ans/2<<endl;
		
	
	return 0;
}