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:       Do you like our new history teacher ?  
 Person2:I'm fed up with his endless talking .  
 Person1:        You can't say that ! He's a very knowledgeable person .  
 Person2:I can't see it . 

informal