program ciur;
 var
    f:text;
    n,i,j,k,a,x:longint;
    ok:boolean;
    v:array[1..10000] of longint;
begin
 assign(f,'ciur.in');
 reset(f);
  read(f,n);
 close(f);
 assign(f,'ciur.out');
 rewrite(f);
  for i:=1 to n do
   begin
    ok:=true;
    j:=2;
    a:=i;
     while (ok) and (j<=a div 2) do
      begin
      if a mod j=0 then
       ok:=false;
       inc(j);
      end;
      if (ok) and (i=a) then
       begin
            inc(k);
            v[k]:=i;
            inc(x);

       end;
      end;
                     writeln(f,x);
                     for k:=1 to x do
            write(f,v[k],' ');
      close(f);
end.