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:       How did you do in the last quiz ?  
 Person2:I doubt if I can pass it .  
 Person1:        Don't be so worried , You know Professor Robert is not too strict .  
 Person2:But I often skip his classes , and he doesn't like me .  
 Person1:        I hope you'll do better in the final .  
 Person2:I must , if I want to pass the course . 

informal