#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 100005
using namespace std;
int n,m,a,b,f[N],cnt,dg[N],ans[N],sz[N];
bool vis[N];
inline int find(int x){return f[x]==x?x:f[x]=find(f[x]);}
int main(){
	freopen("sent.in","r",stdin);
	freopen("sent.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;++i) f[i]=i,sz[i]=1;
	for(int i=1;i<=m;++i){
		scanf("%d%d",&a,&b);
		int u=find(a),v=find(b);++dg[a],++dg[b];
		if(u==v) continue;
		f[v]=u;sz[u]+=sz[v];sz[v]=0;
	}
	for(int i=1;i<=n;++i){
		int u=find(i);
		if(dg[i]%2){ ++ans[u];continue;}
	}
	memset(vis,false,sizeof(vis));
	int As=0;
	for(int i=1;i<=n;++i){ 
		int u=find(i);
		if(!vis[u]&&sz[u]>1) As+=(ans[u]-2<0?0:ans[u]-2)/2+1,vis[u]=true;
	}
	printf("%d\n",As-1);
	return 0;
}