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:       I want to change rooms immediately , plus a refund for tonight .  
 Person2:I'm sorry , sir . Exactly what is the problem ?  
 Person1:        I'm knee-deep in cockroaches !  
 Person2:I'm so sorry , sir . We'll give you a new room immediately , and give you a refund also .  
 Person1:        Thank you . I'm glad that this hotel strives to keep its reputation intact .  
 Person2:Sir , we always try to please our guests . 

formal