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:       Lisa , would you like to go to the library with me ?  
 Person2:OK . Do you think we can go buy a newspaper first ?  
 Person1:        Sure . First we'll go buy a newspaper and then we'll go to the library .  
 Person2:Are we going to walk or drive ?  
 Person1:        The weather is really nice today . Let's walk .  
 Person2:The weather is good now , but I think it's suppose to rain this afternoon .  
 Person1:        Alright , then let's take an umbrella . Is your brother coming with us ?  
 Person2:No , he's still sleeping .  
 Person1:        Wow , it's already 10:00 AM . He must have been up late last night .  
 Person2:Yeah , he didn't come home until 12:00 AM .  
 Person1:        I hope he can come later .  
 Person2:I hope so too . I'll give him a call when we get there .  
 Person1:        How do we get to the library from here ?  
 Person2:It's straight down this road on the left , next to the museum . It takes about 10 minutes . 

informal