#2 #7 #10 WA

#include<bits/stdc++.h>
using namespace std;
inline int read()
{
	int s=0,w=1;char ch=getchar();
	while(ch<'0'||ch>'9')
	{
	if(ch=='-' )w=-1;
	ch=getchar();
	}
	while(ch>='0'&&ch<='9')
	{
	s=s*10+ch-'0';
	ch=getchar();
	}
	return s*w;
}
int w,n,sum,ans;
const int N=3e4+1;
int p[N];
int main()
{
	w=read();n=read();
	for(int i=1;i<=n;i++)	p[i]=read();
	
	sort(p+1,p+1+n);

	int l=1,r=n;
	while(l<r)
	{
		if(p[l]+p[r]<=w)
		{
			l++; r--;
			ans++;
		}
		else
		{
			r--;
			ans++;
		}
	}
	printf("%d\n",ans);
	return 0;
}