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:       What are your plans for this weekend ?  
 Person2:I'd like to hire a bike . I think it would be a good idea to do some cycling on Sunday .  
 Person1:        If the weather's fine .  
 Person2:I am sure it will be . It's been good so far this weekend .  
 Person1:        I know a good place to hire bikes if you want .  
 Person2:Thanks . That would be really helpful .  
 Person1:        But remember , be careful when you ride a bike . The traffic in Beijing can be dangerous . 

informal