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:       What can I do for you ?  
 Person2:I need to make a deposit .  
 Person1:        Are you depositing cash or a check ?  
 Person2:I ’ m depositing a check .  
 Person1:        Please sign the back of the check .  
 Person2:There you go .  
 Person1:        Do you want cash back ?  
 Person2:Yes , please .  
 Person1:        How much cash would you like ?  
 Person2:I want $ 150 .  
 Person1:        Here ’ s your $ 150 .  
 Person2:Thank you , and have a nice day . 

informal