var a:array[1..500000] of int64;
    n,pi,pf:longint;

procedure citire;
var i:longint;
    x,y:int64;
begin
  assign(input,'reguli.in');
  reset(input);
  readln(n);
  readln(x);
  for i:=2 to n do
    begin
      readln(y);
      a[i-1]:=y-x;
      x:=y;
    end;
  close(input);
end;

procedure prel;
var i:longint;
begin
  pi:=1;
  pf:=1;
  for i:=2 to n-1 do
    if a[i]=a[pi] then
      begin
        inc(pi);
        if pi>pf then
          pi:=1;
      end
                  else
      begin
        pf:=i;
        pi:=1;
      end;
end;

procedure afis;
var i:longint;
begin
  writeln(pf);
  for i:=1 to pf do
    writeln(a[i]);
end;

begin
  assign(output,'reguli.out');
  rewrite(output);
  citire;
  prel;
  afis;
  close(output);
end.