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:       Dad , where is the Book Building ?  
 Person2:I'm looking . Can you still remember what the conductor said ?  
 Person1:        She said that when we get off the bus , the Book Building is right by the bus stop .  
 Person2:But I don't see it .  
 Person1:        Oh , Dad , look at the sign , please !  
 Person2:Oh , my god ! We get off at the wrong stop . I'm so sorry , honey .  
 Person1:        OK , Dad , it happens .  
 Person2:It's my fault . So what can we do now ? Walk ?  
 Person1:        Come on , I'm too tired !  
 Person2:OK , you promise don't tell your mother about it , we'll take a taxi .  
 Person1:        Sure , I promise .  
 Person2:If you keep your promise , I will also let you watch Ultraman this evening . 

informal