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:       Have you anything to declare ?  
 Person2:One bottle of perfume and a watch .  
 Person1:        Where did you buy it ?  
 Person2:In Boston .  
 Person1:        Do you travel a lot ?  
 Person2:Oh ... I go to see my sister twice a year or so .  
 Person1:        Twice a year ? How long has your sister lived in Boston ?  
 Person2:Nearly ten years .  
 Person1:        I see , that's a long time . How much was the watch ?  
 Person2:I can't remember , but I've got the receipt somewhere . Would you like to see it ?  
 Person1:        Yes , I'd like to see the receipt . Oh ! I see you bough the watch last week .  
 Person2:Yes . Does that mean I'll have to pay duty on it ?  
 Person1:        Yes , I'm afraid you will . Altogether on the watch and the perfume you owe me seven pounds .  
 Person2:Ok . Here you are . Is that all right now ?  
 Person1:        Yes , that's fine . I hope you enjoyed your stay in Boston ?  
 Person2:Yes , I did . I had a fine time . 

formal