const
  lim=500500;
var
  t:array[1..lim] of int64;
  pi:array[1..lim] of longint;
  i,n,m,k,q:longint;
  x,y:int64;

procedure prefix;
begin
  pi[1]:=0;
  k:=0;
  for q:=2 to n do
  begin
    while (k>0) and (t[k+1]<>t[q]) do k:=pi[k];
    if t[k+1]=t[q] then inc(k);
    pi[q]:=k;
  end;
end;

begin
  assign(input,'reguli.in');
  reset(input);
  readln(n);
  readln(x);
  for i:=2 to n do
  begin
    readln(y);
    t[i-1]:=y-x;
    x:=y;
  end;
  close(input);
  dec(n);
  prefix;
  assign(output,'reguli.out');
  rewrite(output);
  m:=n-pi[n];
  writeln(m);
  for i:=1 to m do
    writeln(t[i]);
  close(output);
end.