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:       What dances do you like ?  
 Person2:I love to dance the fast music .  
 Person1:        Then you must be interested in disco .  
 Person2:Yes , it's my favorite .  
 Person1:        Oh , it's a disco . Let's dance .  
 Person2:You're a good dancer .  
 Person1:        Thank you . Now they are playing a rumba . Would you have a try ?  
 Person2:Sorry . I feel like sitting out the next dance .  
 Person1:        OK . Let's get something to drink .  
 Person2:Good idea . 

informal