Program hotrotinhoc_hoc24;
var i,n,d: integer;
begin
write('Nhap n='); readln(n);
d:=0;
for i:=1 to n do if i mod 2=0 then d:=d+1;
writeln('Co ',d,' so chan tu 1 den n');
write('Cac so chan do la : ');
for i:=1 to n do if i mod 2=0 then write(i,' ');
readln
end.