package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd:=bf.NewReader(Stdin)
	var n,m int
	Fscan(rd,&n,&m)
	c:=make([]int,2*n+2)
	g:=make([][]int,2*n+1)
	for ;m>0;m-- {
		var a,b int
		Fscan(rd,&a,&b)
		g[a]=append(g[a],b)
		g[b]=append(g[b],a)
	}
	v:=make([]bool,2*n+1)
	p:=0
	for i,t:=range g{
		if v[i] {
			continue
		}
		v[i]=true
		p++
		c[p]++
		es:=t[:]
		for len(es)>0 {
			e:=es[len(es)-1]
			es=es[:len(es)-1]
			if v[e] {
				continue
			}
			v[e]=true
			c[p]++
			es=append(es,g[e]...)
		}
		
	}
	var ans int
	for _,v:=range c[2:] {
		ans+=v%2
	}
	ans/=2
	Println(ans)
}