#include <bits/stdc++.h>
using namespace std;
int n,a[30005],w,ans;
int main(){
	// freopen("group.in","r",stdin);
	// freopen("group.out","w",stdout);
	cin>>w>>n;
	for(int i=1;i<=n;i++)	
		cin>>a[i];
	sort(a+1,a+n+1);
	int l=1,r=n;
	while(l<=r){
		if(a[l]+a[r]<=w){
			l++,r--;
			ans++;
		}
		else{
			r--;
			ans++;
		}
	}
	cout<<ans;
	return 0;
}