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:       Welcome . How can we be of service today ?  
 Person2:Hello . My aunt in the US has sent me $ 500 . She sent it yesterday , using the standard service . It's my birthday today , you see .  
 Person1:        Well , happy birthday . If it was sent yesterday using the usual service , it should be here already . You do have an account with us , right ?  
 Person2:Yes . Here's my card . Do you need my ID ?  
 Person1:        Please . Just to double check all the details .  
 Person2:There you go . 

informal