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:       Do you know his sister ?  
 Person2:Her name is Laura , isn't it ?  
 Person1:        That's right .  
 Person2:How old is she ?  
 Person1:        Um ... let me see now , is it 18 or 19 , I can never remember ... 18 ... 19 next birthday . Tthat's it .  
 Person2:What does she look like ?  
 Person1:        Well ...  
 Person2:Pretty , is she ?  
 Person1:        Yes ... quite pretty . 

formal