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'm back .  
 Person2:What have you done ?  
 Person1:        Going shopping . It tires me too much .  
 Person2:Why don't you go shopping online ?  
 Person1:        Can I ?  
 Person2:Why not ? Let me recommend a website .  
 Person1:        OK . What does it sell ?  
 Person2:It sells almost everything you can see in the department .  
 Person1:        That's great . 

informal