public static function find_valid_days($year)
{
$days = 31;
if ($m == 2) {
$days = date('L', strtotime($year . '-01-01')) ? 29 : 28;
// leap year
} elseif ($m == 4 || $m == 6 || $m == 9 || $m == 11) {
$days = 30;
}
if ($m == date('m')) {
$days = date('d');
}
return $days;
}