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:       How was Mei ’ s party on Saturday ? 
 Person2:Oh I didn ’ t go . I stayed at home with my family . 
 Person1:        Oh really ? What did you do ? 
 Person2:We watched lots of television and films . 
 Person1:        I see . Anything else ? 
 Person2:Yes , we ate a delicious meal and drank some very good wine . 
 Person1:        Well , it sounds like you really enjoyed yourself . 

informal