como adicionar botão no UIAlertController no IOS 9

como usamosUIAlertView no iOS 9 e como adicionar o botãoUIAlertController

UIAlertController * alert=[UIAlertController 

alertControllerWithTitle:@"Title" message:@"Message"preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction* yesButton = [UIAlertAction
                        actionWithTitle:@"Yes, please"
                        style:UIAlertActionStyleDefault
                        handler:^(UIAlertAction * action)
                        {
                            **//What we write here????????**


                        }];
UIAlertAction* noButton = [UIAlertAction
                            actionWithTitle:@"No, thanks"
                           style:UIAlertActionStyleDefault
                           handler:^(UIAlertAction * action)
                           {
                               **//What we write here????????**

                           }];

[alert addAction:yesButton];
[alert addAction:noButton];

[self presentViewController:alert animated:YES completion:nil];

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