program economie;
type vector=array[1..1000] of word;
var v,m:vector;
    f,g:text;
    n,i,min,j:word;
    ok:boolean;

procedure sortare(var v:vector);
var j,aux,k:integer;
begin
for i:=1 to n-1 do
	begin
    k:=i;
    for j:=i+1 to n do
    if v[j]<v[k] then
    k:=j;
    if k>i then
      begin
      aux:=v[i];
      v[i]:=v[k];
      v[k]:=aux;
      end;
   end;
end;

procedure back_rec (numar:integer);
var ii:word;
begin
ii:=1;
while (ii<=min)and not ok do
  begin
  if numar-m[ii]>0 then
    back_rec (numar-m[ii])
  else
    if numar-m[ii]=0 then
      ok:=true;
  ii:=ii+1;
  end;
end;








procedure incercare;
begin
for i:=2 to n do
begin
  ok:=false;
  back_rec(v[i]);
  if not ok then
    begin
    min:=min+1;
    m[min]:=v[i];
    end;
end;
end;





begin
assign(f,'economie.in');
reset(f);
assign(g,'economie.out');
rewrite(g);
read(f,n);
for i:=1 to n do
read(f,v[i]);
sortare(v);
if v[1]=1 then
begin
  writeln(g,1);
  write(g,1);
end
else
begin
min:=1;
i:=2;
m[1]:=v[1];
incercare;
writeln(g,min);
for j:=1 to min do
if j<>min then
   writeln(g,m[j])
   else
   write (g,m[j]);
end;
close(f);
close(g);
end.