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:       May I speak to Mr . Smith ?  
 Person2:He is at the warehouse this morning .  
 Person1:        What time do you expect him back ?  
 Person2:Sorry , I have no idea . You can call him there if you like .  
 Person1:        Ok , I have the number . Bye ! 

formal