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 help you ?  
 Person2:Yes , I want to buy a suit .  
 Person1:        What about the red one ? It's the best seller .  
 Person2:Yeah , it's quite cute . I don't think it will fit me . I would prefer a darker color . Have you a black one ?  
 Person1:        Yes , We have . 

formal