package main

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

func main() {
	rd := bf.NewReader(Stdin)
	var n, m int
	Fscan(rd, &n, &m)
	opened := make([]bool, n+1)
	for i := 0; i < m; i++ {
		var a int
		Fscan(rd,&a)
		opened[a] = true
	}
	f := make([][]int, 2e5+1)
	for i := 1; i < len(f); i++ {
		for j := i; j < len(f); j += i {
			f[j] = append(f[j], i)
		}
	}
	ans := 0
	s := make([]int, n+1)
	for i := n; i >= 1; i-- {
		if opened[i] == ((n/i+s[i])%2==1) {
			continue
		}
		// println(i)
		ans++
		for _, e := range f[i] {
			s[e]++
		}
	}
	Println(ans)
}