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:       who are you writing a letter to ? 
 Person2:I'm just responding to Sue's letter . Do you want to help ? 
 Person1:        OK . I guess I could add something . Tell them that I send my love . 
 Person2:that's kind of boring . Don't you want to tell them anything else ? 
 Person1:        well , maybe you could tell them about my promotion . 
 Person2:you've been promoted ? when did that happen ? 
 Person1:        just today . I guess I forgot to mention it . 
 Person2:congratulations ! That's really exciting ! Let's get out a bottle of wine to celebrate ! 
 Person1:        shouldn't we finish writing this letter first ? 
 Person2:ah . That can wait . Your promotion is the best news I've heard in a long time ! 
 Person1:        it is good news , but it looked like you were almost finished . We might as well just sign off . 
 Person2:ok , you're right . I'll just tell them how round I am of you for getting a promotion and then I'll thank Sue for her kind letter . 
 Person1:        I guess you can write that I'm looking forward to seeing them in June . 
 Person2:that's thoughtful of you . 
 Person1:        and also thank them from the bottom of my heart for the Christmas package they sent us . 
 Person2:that's right ! I almost forgot about that . 
 Person1:        what would you do without me ? 
 Person2:we do balance each other out well . I guess we were really made for each other ! 

informal