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:       Song , I hate to say goodbye , but I have to .  
 Person2:Nice meeting you , Kevin . I hope to see you again .  
 Person1:        Let's keep in touch .  
 Person2:Sure , let's . Goodbye , then . 

informal