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'.

 Person1:       Excuse me , Ma ' am . I would like to mail this package door to door via airmail to London . It is a very important package and has to be sent within 3 days . 
 Person2:No problem . But , the postage is much higher than the regular package . 
 Person1:        That's fine with me . I am willing to pay for it as long as you can guarantee me the package can arrive in time . 
 Person2:OK . All the registered airmail packages can be received in 5 working days . 
 Person1:        I see . How much do I need to pay in total for this package ? 
 Person2:It's 500 dollars . 
 Person1:        Can I have the receipt ? Just in case I can trace it if something goes wrong . 
 Person2:Sure ! Please just fill in your I . D . number and ways to contact you here . 
 Person1:        Do I need to include my zip code in the address ? 
 Person2:You had better include that because it is easier for the mailmen to find the correct mailing address . 
 Person1:        Thank you very much . Here is 500 dollars . 
 Person2:Here is your receipt . Contact us if your friend still doesn't receive the package after 5 work days . 
informal