#include <iostream>
#include <cstring>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
const int maxn=100005;
int deg[maxn];
int ufs[maxn];
bool haveodd[maxn];
int find(int x)
{
    return x==ufs[x]?x:ufs[x]=find(ufs[x]);
}
void link(int a,int b)
{
    ufs[find(a)]=find(b);
}
int main()
{
    freopen("sent.in","r",stdin);freopen("sent.out","w",stdout);
    int n,m;scanf("%d %d",&n,&m);
    int a,b;
    while(m--)
	{
        scanf("%d %d",&a,&b);
        deg[a]++;deg[b]++;
        link(a,b);
    }
    
    int cnt1=0,cnt2=0;
    for(int i=1;i<=n;++i)
	{
        if(deg[i]&1)haveodd[find(i)]=true,cnt2++;
        if(!haveodd[i]&&ufs[i]==i)cnt1++;
    }
    if(cnt2==0)
	{
        printf("%d\n",cnt1-1);
    }
	else
	{
        printf("%d\n",cnt2/2-1+cnt1);
    }
    fclose(stdin);fclose(stdout);   
    return 0;
}