#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
using namespace std;
inline void _read(int &d)
{
	char t=getchar();bool f=false;
	while(t<'0'||t>'9'){if(t=='-')f=true;t=getchar();}
	for(d=0;t>='0'&&t<='9';t=getchar())d=d*10+t-'0';
	if(f==true)d=-d;
}
int n,m;
int du[110000];
int main()
{
	freopen("sent.in","r",stdin);
	freopen("sent.out","w",stdout);
	int a,b,c,d,e;
	_read(n);_read(m);
	for(a=1;a<=m;a++)
	{
		_read(b);_read(c);
		du[b]++;du[c]++;
	}
	int tot=0;
	for(a=1;a<=n;a++){du[a]%2==1;tot++;}
	cout<<tot/2-1;
	return 0;
}