Here is my code. What is wrong? Help, please!

var m,n:int64;
k,i:0..20;
a:array[1..20] of int64;

begin
  read(n,k);
  for i:=1 to k do
  read(a[i]);
  for i:=2 to k do
  if a[i]<a[i-1] then
  begin
      m:=a[i];
      a[i]:=a[i-1];
      a[i-1]:=m
  end;
  m:=n-(n-a[1])-(n-a[2]);
  if m<=0 then write(0) else write(m);
end.

Edited by author 02.11.2013 04:21

You must only write((a1+a2+...+ak)-n)
That's all))
Good luck!

no, right answer is ((a1+a2+...+ak)-n * (k-1))