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:       You seem to be very tired .  
 Person2:Yes , I have been working for eight hours .  
 Person1:        Why don't you join us to go out for a walk ?  
 Person2:No , really . I'm not in the mood for it . 

informal