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:       Hey , Mary , nice to see you again . I heard you're going back home to the U . S .  
 Person2:Yes . I'm leaving tomorrow . I came here just because I want to say good-bye to you .  
 Person1:        You're so thoughtful . Wish you a good trip home . And we'll miss you .  
 Person2:I'll miss you too , my friends . 

informal