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:       I would like to buy some beef .  
 Person2:What kind do you want ?  
 Person1:        I need to get ground beef .  
 Person2:How many pounds would you like me to get you ?  
 Person1:        I need about four pounds .  
 Person2:Exactly what type of ground beef do you want ?  
 Person1:        Extra lean .  
 Person2:I'll get that for you right now .  
 Person1:        I appreciate that .  
 Person2:Don't mention it , I'll just wrap this up for you .  
 Person1:        Thanks for your help . 

informal