program economie;
type vector=array[1..1000] of word;
     vector1=array[1..50000] of boolean;
var v,m:vector;
    c:vector1;
    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 incercare;
var ii:word;
begin
ii:=2;
repeat
c[m[min]]:=true;
for i:=1 to (v[n]-m[min])  do
  if c[i] then
    c[i+m[min]]:=true;
while (ii<=n)and c[v[ii]] do
  ii:=ii+1;
if ii<=n then
  begin
  min:=min+1;
  m[min]:=v[ii];
  end;
until ii>n;
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;
m[1]:=v[1];
incercare;
writeln(g,min);
for i:=1 to min do
if i<>min then
   writeln(g,m[i])
else
    write(g,m[i]);
end;
close(f);
close(g);
end.