private static void setTask(AlarmManager alarmManager, long triggerAtMillis, PendingIntent operation) {//RTC
        if (Build.VERSION.SDK_INT >= 23) {
            alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, triggerAtMillis, operation);
        } else if (Build.VERSION.SDK_INT >= 19) {
            alarmManager.setExact(AlarmManager.RTC_WAKEUP, triggerAtMillis, operation);