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 kind of music do you like ?  
 Person2:I like popular music best .  
 Person1:        Me too .  
 Person2:Who is your favorite singer ?  
 Person1:        Qi In is .  
 Person2:Do you know this song ?  
 Person1:        Yes , I like it very much .  
 Person2:Let's sing it together , shall we ?  
 Person1:        No problem . 

formal