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:       Susan has got married .  
 Person2:Really ? How do you know that ?  
 Person1:        Her marriage was a hole and corner affair .  
 Person2:Why ? That ’ s good news , but no one knows it ?  
 Person1:        I have no idea . Maybe she didn ’ t want to let us ... , so ... 

informal