#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int a,b[30001],n,ans=0,h=0,t;
void input(){
	cin>>a>>n;
	for(int i=1;i<=n;i++) scanf("%d",&b[i]);
}
void work(){
	sort(b+1,b+n+1);t=n;
	while(h<t){
		if(b[h]+b[t]>a){
			t--;ans++;
		}
		else{
			h++;t--;ans++;
		}
	}
	if(h==t) cout<<ans+1;
	else cout<<ans;
}
int main(){
	freopen("group.in","r",stdin);
	freopen("group.out","w",stdout);
	input();
	work();
	return 0;
}