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:       We're having a tailgate party I before the game . Would you like to join us ? 
 Person2:Okay . But what is a tailgate party ? 
 Person1:        Someone brings a truck to the game and we have a barbecue right there in the parking lot out of the back of the truck ! 
 Person2:How fun ! Can I bring something ? 
 Person1:        Don't worry about it ! Just come at five . 
 Person2:I make a mean potato salad ! 
 Person1:        Well , if you insist , you are welcome to bring a potato salad ! 
 Person2:Then I'll see you in the parking lot at five ! Thank you ! 

informal