Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.
Input:  Person1:       Are you going out again ?  
 Person2:Yes , I'm going to the cinema , dad .  
 Person1:        You mustn't go to bed very late . Can you be home before nine .  
 Person2:Oh , I won't be back so early . The film will be over at nine . Can I have the key to the bicycle ?  
 Person1:        No . I won't let you ride a bicycle late at night .  
 Person2:Oh , dad , I'm not a child . I'm 17 already . I'll come back as soon as the film is over .  
 Person1:        OK . Here's the key . Take care .  
 Person2:I will . Thank you , dad . 

informal