program econ;
var x,a:array[1..1000] of longint;
n,i,j,k:longint;
f,g:text;
sort,sol:boolean;
begin
  assign(f,'economie.in'); assign(g,'economie.out');
  reset(f); rewrite(g);
  read(f,n);
  for i:=1 to n do read(f,x[i]);
  sort:=false;
  while not sort do
  begin
  sort:=true;
  for i:=1 to n-1 do
    if x[i]>x[i+1] then begin j:=x[i]; x[i]:=x[i+1]; x[i+1]:=j; sort:=false; end;
  end;
  j:=1; a[j]:=x[1];
  for i:=2 to n do
  if x[i]<>x[i-1] then begin j:=j+1; a[j]:=x[i]; end;
  n:=j;
  sol:=true;
  for i:=2 to n do
    if a[i] mod a[1]<>0 then sol:=false;
  if sol then begin writeln(g,'1'); writeln(g,a[1]); end
  else
  begin
    sol:=true;
    for i:=3 to n do
    if ((a[i] mod (a[1]+a[2])) mod a[1] <>0) and
    ((a[i] mod (a[1]+a[2])) mod a[2]<>0) then sol:=false;
    if sol then begin writeln(g,'2'); writeln(g,a[1]); writeln(g,a[2]); end
    else begin writeln(g,'3'); writeln(g,a[1]); writeln(g,a[2]); writeln(g,a[3]); end;
  end;
  close(f); close(g);
end.