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:       I'm glad we live in a small town .  
 Person2:Why ?  
 Person1:        Because the houses look so nice at Christmas time .  
 Person2:Yes , they do . Do you have a Christmas tree this year ?  
 Person1:        Yes , we have a big tree this year . I bought the decorations at the five-and-tencent store yesterday . Do you want to come and see it ?  
 Person2:I can't now because I have to buy a present for my mother .  
 Person1:        When can you come ?  
 Person2:I don't know when I can come . I'll let you know later . 

formal