program ex;
type
 ss=array[1..30000]of integer;
var
 a:ss;
 w,n:integer;
 f1,f2:text;
 min:integer;
procedure init;
 var
  i:integer;
 begin
  assign(f1,'group.in');
  assign(f2,'group.out');
  reset(f1);
  rewrite(f2);
  readln(f1,w);
  readln(f1,n);
  for i:=1 to n do
   readln(f1,a[i]);
 end;

procedure qsort(l,r:integer);
 var
  i,j,x,y:integer;
 begin
  i:=l;
  j:=r;
  x:=a[(l+r)div 2];
  repeat
   while a[i]<x do inc(i);
   while a[j]>x do dec(j);
   if 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 qsort(l,j);
  if i<r then qsort(i,r);
 end;
procedure main;
 var
  i,j:integer;
 begin
  min:=0;
  i:=n;j:=1;
  while (j<=i) do
   begin
    if (a[i]+a[j]<=w)and(j<i) then
       begin
        inc(j);
        dec(i);
       end
       else dec(i);
    inc(min);
   end;
 end;
begin
 init;
 qsort(1,n);
 main;
 write(f2,min);
 close(f1);
 close(f2);
end.