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:       Can I help you ? 
 Person2:I want to buy a hat . 
 Person1:        Come here , please . 
 Person2:Is this one fit for you ? It is nice . 
 Person1:        I don't like the style . 
 Person2:How about this one ? 
 Person1:        Black is not my favorite colour . 
 Person2:You must like this pink one , don't you ? 
 Person1:        It's pretty . How much is it ? 
 Person2:Fifty yuan . 
 Person1:        It's too expensive . Can you come down a little ? 
 Person2:How about forty-five ? 
 Person1:        I'll buy it if forty . 
 Person2:OK . 

informal