#include<stdio.h>
int a[200005];
int t[200005], s[200005];
int main()
{
	int n, m;
	scanf("%d %d", &n, &m);
	int i, j;
	for (i = 0; i < m; i++)
		scanf("%d", &a[i]);
	for (i = 1; i <= n; i++)
		t[i] = n / i % 2;
	for (i = 0; i <= n; i++)
		s[i] = 0;
	for (i = 0; i < m; i++)
		s[a[i]] = 1;
	int ans = 0;
	for (i = n; i > 0; i--)
	{
		if (s[i] == t[i])
			continue;
		ans++;
		for (j = 1; j * j <= i; j++)
		{
			if (i % j > 0)
				continue;
			s[j] ^= 1;
			if (j * j < i)
				s[i / j] ^= 1;
		}
	}
	printf("%d\n", ans);
	return 0;
}