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:       Thank you for calling ABC Company , may I help you ?  
 Person2:I ’ m Liu Yi . I ’ d like to speak to Mr . Smith .  
 Person1:        Sorry , we have two Smiths , Robert Smith and James Smith , which one would you like to speak to ?  
 Person2:I ’ d like to speak with Mr . Robert Smith .  
 Person1:        He is on the line . 

formal