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:       Merry Christmas , Lily . 
 Person2:The same to you , Joey . 
 Person1:        This is your first Christmas in the US . Here is the gift for you . 
 Person2:It's very thoughtful of you . Wow , it is so beautiful . Could you tell me how American people celebrate Christmas ? 
 Person1:        Ok . People decorate their houses , place a Christmas tree in the room and maybe sing a Christmas carol together . 

informal