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:       Who is it ?  
 Person2:Open the door . It's me . I can't find the key .  
 Person1:        You're always so careless .  
 Person2:Oh , thank you . I am exhausted . Will you bring me a cup of tea ?  
 Person1:        Okay , but I haven't prepare supper .  
 Person2:So let's eat out .  
 Person1:        What do you want to eat ?  
 Person2:Noodles . How about you ?  
 Person1:        Dumplings . 

formal