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:       Excuse me . Can you show me some nail-polish ?  
 Person2:Yes . We have all kinds of colors for it .  
 Person1:        That's good .  
 Person2:What's your favorite color ?  
 Person1:        In my opinion , orange is very nice .  
 Person2:Sometimes pink is not bad , too .  
 Person1:        You're right . Well , just these two , please .  
 Person2:Thank you . Anything else ?  
 Person1:        No , thanks . 

informal