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 I need a visa ?  
 Person2:No , I shouldn't think so . But you must take your passport of course .  
 Person1:        Yes , I know . I must get my traveler's check and some foreign currency .  
 Person2:Yes , you need the traveler's check but you needn't get any foreign currency . You can have my US Dollars , I don't need them .  
 Person1:        Really ? That's very good of you , Helen . But I must get a new suitcase , my old one needs repairing .  
 Person2:You needn't buy one . You can have mine .  
 Person1:        That's very kind of you , Helen . I hope you don't mind my leaving you like this . I need a holiday . It won ’ t be long .  
 Person2:Don't be silly , John . I'm going with you . It's necessary for me to have a holiday too . 

informal