var v:array[0..2000001]of boolean;
    p:array[1..1024]of longint;
    n,j,k,u,i:longint;
    f:text;
begin
   assign(f,'ciur.in');
   reset(f);
   read(f,n);
   close(f);
   for i:=2 to n do
   if not v[i] then begin j:=i;
                        while j<n do
                        begin
                        j:=j+i;
                        v[j]:=true;
                        end;
                  end;
   i:=n+1;
   repeat
   i:=i-1;
   if not v[i] then begin u:=u+1;
                          p[u]:=i;
                    end;
   until(i=2)or(u=1000);
   assign(f,'ciur.out');
   rewrite(f);
   writeln(f,u);
   for i:=u downto 1 do
   write(f,p[i],' ');
   writeln(f);
   close(f);
end.