# include <iostream>
# include <cstdio>
# include <algorithm>
using namespace std;

int n,w,ans=0;
int p[30005];

int main()
{
	freopen("group.in", "r", stdin);
	freopen("group.out", "w", stdout);
	
	scanf("%d%d", &w, &n);
	for (int i=1;i<=n;++i)  scanf("%d", &p[i]);
	sort(p+1,p+n+1);
	int i=1,j=n;
	while (i<=j)
	{
		if (p[i]+p[j]<=w)  i++,j--,ans++;
		else j--,ans++;
	}
	if (i==j)  ans++;
	printf("%d\n", ans);
	
	return 0;
}