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 can I do for you ?  
 Person2:Do you have any blue shirts ?  
 Person1:        Yes . What's your size ?  
 Person2:I'm not familiar with American size .  
 Person1:        All right . Let me see . I think you'd wear a size 8 . This shirt is size 8 .  
 Person2:It's pretty . May I try it on ?  
 Person1:        Sure . The fitting room is over there .  
 Person2:Thank you . 

informal