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:       Do you want to buy a sweater ?  
 Person2:Yes . Which one is the latest ?  
 Person1:        The cowl-neck pullovers are new in . It sells like hot cakes .  
 Person2:It's my style . Will it be resistance to balling ?  
 Person1:        Of course . The brand is Bird and it's famous for its quality . 

formal