#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#define maxn 30001
using namespace std;
int w,n,p[maxn];int ans=0;
inline void readln(){
	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]);
	}
}
inline void work(){
	sort(p+1,p+n+1);
	int l=1,r=n;
	while(l<=r){
		if (p[l]+p[r]<=w){
			ans++;l++;r--;
		}
		else {
			ans++;r--;
		}
	}
	printf("%d\n",ans);
}
int main(){
	readln();
	work();
	fclose(stdin);fclose(stdout);
	return 0;
}