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:       The weekend's finally here ! 
 Person2:And it's a long one . I have Monday off . It's Memorial Day or something like that . 
 Person1:        Yep . It's the kickoff of the barbecue season . We're invited to a grill party in the park tomorrow . 
 Person2:Sounds good . What do we need to bring ? 
 Person1:        We need to buy some buns for the hot dogs and hamburgers , and I'm making potato salad . 
 Person2:I'll dig out the Frisbee and my kite from Taiwan . 

informal