var v:array[1..2000000]of byte;
    n,i,j,k:longint;
begin
assign(input,'ciur.in');reset(input);
assign(output,'ciur.out');rewrite(output);
read(n);
 for i:=2 to trunc(sqrt(n)) do
  if v[i]=0 then begin inc(k);for j:=2 to n div i do v[i*j]:=1;end;
 j:=0;
 writeln(k);
 for i:=n downto 2 do
  if v[i]=0 then begin
   k:=i;
   inc(j);
   if j=1000 then break;
  end;
 for i:=k to n do if v[i]=0 then write(i,' ');
close(input);close(output);
end.