public static function isLeapYear($year) {
	    $mod = ($year % 33);
	    if (($mod == 1) or ( $mod == 5) or ( $mod == 9) or ( $mod == 13) or ( $mod == 17) or ( $mod == 22) or ( $mod == 26) or ( $mod == 30)) {
	        return true;
	    }
	    return false;
	}