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:       Would you find any other available flight to Tokyo ? 
 Person2:Sure . We try our best . 
 Person1:        Thank you . 
 Person2:Mr.Chen , are you sure you're taking BA - 007 back to Tokyo ? 
 Person1:        Yes , of course . I think our travel agent would have made the reservation for us . 
 Person2:I'm afraid this flight is all booked up . 
 Person1:        Are you sure ? We can't really take it ? I reconfirmed with Miss Peterson the other day . 
 Person2:I'm afraid so except we have many no-show passengers . 

formal