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:       What a wonderful party ! I had a good time . How about you ?  
 Person2:I enjoyed myself , too .  
 Person1:        Shall I give you a ride home ?  
 Person2:Yes , if it's not too much of a trouble .  
 Person1:        It's no trouble at all because your house is on the way to my place .  
 Person2:That's great . Let's go ! 

informal