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 know Sally ?  
 Person2:Sally ? She is a bachelor girl . She is an excellent designer . Many of the company's advertisements are her child trains .  
 Person1:        Why is she still single ? She must have a face that would stop a clock .  
 Person2:Oh , quite the other way round . She is a knock-out . She devotes much of her time to her career . 

informal