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:       Can I pay my bill here ?  
 Person2:Yes , sir .  
 Person1:        How much is the charge ?  
 Person2:Let me see ... it's $ 50 .  
 Person1:        Do you receive checks ?  
 Person2:Sorry , sir . We receive credit card and cash only .  
 Person1:        Here is my card . 

informal