package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"

	"github.com/monkukui/ac-library-go/dsu"
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Buffer(make([]byte, 1<<20), 1<<20)
	sc.Split(bufio.ScanWords)
	next := func() int {
		sc.Scan()
		x, _ := strconv.Atoi(sc.Text())
		return x
	}
	n, m := next(), next()
	d := dsu.New(n)
	for i := 0; i < m; i++ {
		u := next()
		v := next()
		d.Merge(u, v)
	}
	c := 0
	for i := 0; i < n; i++ {
		if d.Leader(i) == i {
			c++
		}
	}
	fmt.Println(c)
}