#include <fstream>
#include <algorithm>
#define N 100010
using namespace std;
int n,m,cnt=0;
int f[N]={0},g[N]={0};
int x[N]={0},size[N]={0},sum=0;
int num[N]={0};
bool l[N]={0};
ifstream in("sent.in");
ofstream out("sent.out");
int ufs(int x)
{
	if(f[x]==x)return x;
	return f[x]=ufs(f[x]);
}
void link(int x,int y)
{
	if(ufs(x)==ufs(y))return ;
	//f[x]=y;
	if(g[x]>g[y])f[y]=x;
	else
	{
		f[x]=y;
		if(g[x]==g[y])g[y]++;
	}
}
void read()
{
	int i,u,v;
	in>>n>>m;
	for(i=1;i<=n;i++)f[i]=i;
	for(i=1;i<=m;i++)
	{
		in>>u>>v;
		link(u,v);
		num[u]++;
		num[v]++;
	}
}
void work()
{
	int i,o,solo=0;
	for(i=1;i<=n;i++)num[i]%=2;
	for(i=1;i<=n;i++)
	{
		o=ufs(i);
		//out<<o<<endl;
		//if(num[i])x[o]++;
		if(num[i])sum++;
		if(!l[o])
		{
			l[o]=1;
			solo++;
		}
	}
	sum/=2;
	if(solo>1)sum--;
	out<<sum<<endl;
}
int main()
{
	read();
	work();
	return 0;
}