Back button not showing on UINavigationController

I have 3 views. The first is a login, the second is a menu, and the third is the result of each part of the menu. I want that when the user logs in, the back button won't appear in the second view. This part works but when I go through the third view, it is hidden too. I've created a fourth view and when I enter, the back button appears and it lets me go back until the second view.

For hiding th开发者_StackOverflow中文版e back button, I've set this only in the second view:

- (void)viewDidLoad {
    self.navigationItem.hidesBackButton = YES;
}

I've also tried to set the opposite in the third view and it don't show.

Why it is not showing on the third view?

do this in secondViewController(after the login one)

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    self.navigationItem.hidesBackButton = NO;
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    self.navigationItem.hidesBackButton = YES;
}