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:       Good evening ! I don't believe we've met before . May I introduce myself ? My name is Jack . 
 Person2:It's a pleasure to meet you . My name is Lucy . 
 Person1:        I'm very happy to meet you . You're from the United States , aren't you ? 
 Person2:Yes , I'm from Salt Lake City . 
 Person1:        I've been to Salt Lake City a few times . I really like your city . 
 Person2:I'm glad to hear that . I think it's the nicest city in the United States . 

informal