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 do you think ? 
 Person2:It looks great . 
 Person1:        I would like to purchase it . 
 Person2:Will this be cash or charge ? 
 Person1:        Here , take my credit card . 
 Person2:Just sign here , please . 
 Person1:        Sure . Here you go . 
 Person2:Here's your receipt . Have a nice day . 

informal