program cch(input,output);
var
  a:array[1..30000] of integer;
  i,j,w,n,ans:integer;

procedure qsort(l,r:integer);
var
 i,j,x,temp:integer;
begin
 i:=l; j:=r;
 x:=a[(l+r) div 2];
 repeat
  while x>a[i] do inc(i);
  while x<a[j] do dec(j);
  if i<=j then
   begin
    temp:=a[i]; a[i]:=a[j];
    a[j]:=temp;
    inc(i); dec(j);
   end;
 until i>j;
 if i<r then qsort(i,r);
 if j>l then qsort(l,j);
end;

begin
 assign(input,'group.in');
 assign(output,'group.out');
 reset(input);
 rewrite(output);
 readln(w);
 readln(n);
 for i:=1 to n do
  readln(a[i]);
 qsort(1,n);
 i:=1; j:=n;
 ans:=0;
 while i<j do
  begin
   if a[i]+a[j]<=w then inc(i);
   inc(ans); dec(j);
  end;
 if i=j then inc(ans);
 write(ans);
 close(input);
 close(output);
end.