C++ :

#include <cstdlib>
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
	int max,n,s=0;
	vector<int>a;a.push_back(0);
	scanf("%d%d",&max,&n);
	for(int i=1;i<=n;i++)
	{
		int in;
		scanf("%d",&in);
		s++;
		a.push_back(in);
	}
	sort(a.begin(),a.end());

	while(a.size()>2)
	{
		if(a.size()>=3)
		{
			if(a[1]+a[2]>max) break;
		}
		for(int i=a.size()-1;i>=2;i--)
		{
			if(a[i]+a[1]<=max)
			{
				s--;
				a.erase(a.begin()+1);
				a.erase(a.begin()+i-1);
				break;
			}
		}
	}
	printf("%d",s);
	return 0;
}

Pascal :

program jco41;
 type tlist=array[1..30005]of longint;
 var
  f:tlist;
  n,w:longint;
  i,j,k,l:longint;
  ans:longint;
  head,tail:longint;
 procedure qsort(var a:tlist;n:longint);
    procedure sort(l,r:longint);
      var i,j,x,y: longint;
      begin
         i:=l;
         j:=r;
         x:=a[(l+r) div 2];
         repeat
           while a[i]<x do
            inc(i);
           while x<a[j] do
            dec(j);
           if not(i>j) then
             begin
                y:=a[i];
                a[i]:=a[j];
                a[j]:=y;
                inc(i);
                dec(j);
             end;
         until i>j;
         if l<j then
           sort(l,j);
         if i<r then
           sort(i,r);
      end;
    begin
       sort(1,n);
    end; 
 begin
  readln(w);
  readln(n);
  for i:=1 to n do
   begin
    readln(f[i]); 
   end;
  qsort(f,n);
  head:=1;
  tail:=n;
  ans:=0;
  repeat
   if f[head]+f[tail]>w then
    begin
     inc(ans);
     dec(tail); 
    end
    else
    begin
     inc(ans);
     inc(head);
     dec(tail); 
    end;
  until (head>tail);
  writeln(ans);
 end.