Я пытаюсь установить таймер обратного отсчета до определенной даты. Я использую:

-(void) viewWillAppear:(BOOL)animated {

    NSString *str =@"12/27/2013";
    NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
    [formatter setDateFormat:@"MM/dd/yyyy"];
    NSDate *date = [formatter dateFromString:str];

    NSTimeInterval numberOfSecondsUntilSelectedDate = [date timeIntervalSinceNow];
    NSInteger numberOfDays = numberOfSecondsUntilSelectedDate / 86400;


    startTime = [[NSDate date] retain];

    secondsLeft = numberOfDays;
    NSLog(@"number%f", numberOfSecondsUntilSelectedDate);
    [self countdownTimer];

}
- (void)updateCounter:(NSTimer *)theTimer {
    if(secondsLeft > 0 ){
        secondsLeft -- ;
        days = secondsLeft / 86400;
        NSLog(@"%d", days);
        hours = secondsLeft / 3600;
        minutes = (secondsLeft % 3600) / 60;
        seconds = (secondsLeft %3600) % 60;
        myCounterLabel.text = [NSString stringWithFormat:@"%02d Days %02d Hours %02d Minutes %02d Seconds", days, hours, minutes, seconds];
    }
    else{
        secondsLeft = 16925;
    }
}

-(void)countdownTimer{

    secondsLeft = hours = minutes = seconds = 0;
    if([timer isValid])
    {
        [timer release];
    }
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateCounter:) userInfo:nil repeats:YES];
    [pool release];
}

Тем не менее, день продолжает выходить как 0. Что я делаю не так?