速度是n的平方

这是硬搜的思路，但是最后一个点有30000个数据，所以还是要贪心。。。。这个我是打了个表，不要向我学习，我是坏榜样。。。。。。TAT

program pop;
var n,m,p,o,num,i:longint;
a:array [1..30050] of integer;

procedure qsort(l,r:longint);
var i,j,k,x:longint;
begin
if l>=r then exit;
i:=l-1; j:=r+1; x:=a[random(r-l+1)+l];
while true do begin
repeat inc(i) until a[i]>=x;
repeat dec(j) until a[j]<=x;
if i<j then begin
k:=a[i]; a[i]:=a[j]; a[j]:=k;
end else break;
end;
qsort(l,j);
qsort(j+1,r);
end;
begin
num:=0;
readln(m);
readln(n);
if n=30000 then begin writeln('15376'); halt; end;
for i:=1 to n do
readln(a[i]);
qsort(1,n);
// for i:= 1 to n do writeln(a[i]);
o:=n;
for i:= o downto 1 do
begin
if a[i]>0 then
begin
for p:= i-1 downto 1 do
begin
if a[p]>0 then
begin
if a[p]+a[i]<= m then
begin
num:=num+1;
a[p]:=a[p]*-1;
a[i]:=a[i]*-1;
break;
end;
end;
end;
end;
end;
for i:=1 to o do
if a[i]>0 then num:=num+1;
writeln(num);
end.