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:       The music has started .  
 Person2:How do you like this waltz ?  
 Person1:        It's very nice .  
 Person2:May I ask you for a dance ?  
 Person1:        Certainly .  
 Person2:You are doing the waltz wonderfully well .  
 Person1:        Thanks . I'm glad you say so . Oh , the music has stopped . 

informal