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:       Excuse me , is this seat taken ?  
 Person2:No , please feel free .  
 Person1:        Thanks a lot .  
 Person2:Do you work in Shanghai ?  
 Person1:        Yes I do . How about you ?  
 Person2:No , I'm a tourist . This place is amazing ! It's much bigger than I imagined , and much more exciting ! There's so much to see here .  
 Person1:        You can say that again ! It's much more modern than people imagine . Where are you from ?  
 Person2:Um , well let's see ... I'm from Kansas originally . A much quieter and more peaceful place than here , that's for sure !  
 Person1:        Uh huh ... 

informal