#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int n,m,Index[100005],ans,r[100005],tot;
int Copy[100005],cnt;
struct DATE {
	int to,next;
} c[1000005];
void add(int x,int y) {
	c[++tot]=(DATE) {
		y,r[x]
	}; r[x]=tot;
}
bool vis[100005];
void dfs(int u) {
	vis[u]=true;
	Copy[++cnt]=u;
	for(int i=r[u]; ~i; i=c[i].next) {
		if(!vis[c[i].to]) {
			dfs(c[i].to);
		}
	}
}
int main() {
	freopen("sent.in","r",stdin);
	freopen("sent.out","w",stdout);
	scanf("%d%d",&n,&m);
	memset(r,0xff,sizeof(r));
	for(int x,y,i=1; i<=m; ++i) {
		scanf("%d%d",&x,&y);
		++Index[x],++Index[y];
		add(x,y),add(y,x);
	}
	for(int now=0,i=1; i<=n; ++i,now=cnt=0) {
		if(!vis[i]) {
			dfs(i);
			if(cnt!=1) ++ans;
			for(int j=1; j<=cnt; ++j) {
				if(Index[Copy[j]]&1) ++now;
			}
			if(now>2) ans+=(now>>1)-1;
		}
	} 
	cout<<ans-1;
	return 0;
}