var n,i,j:longint;
    s:array[0..1000] of longint;
    v:array[1..2000001] of byte;
f,g:text;
begin
assign(f,'ciur.in');
reset(f);
assign(g,'ciur.out');
rewrite(g);
readln(f,n);
for i:=2 to trunc(sqrt(n)) do
       if v[i]=0 then begin
       for j:=2 to (n div i) do
           v[i*j]:=1;
           end;
for i:=2 to n do
if v[i]=0 then begin
              s[0]:=s[0]+1;
                s[s[0]]:=i;
                end;
writeln(g,s[0]);
if s[0]>=1000 then
        for i:=s[0]+1-1000 to s[0] do
                    write(g,s[i],' ')
else
for i:=1 to s[0] do
write(g,s[i],' ');
writeln(g);
close(f);
close(g);
end.