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:       Hello , I need to register for a class .  
 Person2:What class are you trying to take ?  
 Person1:        I want to take a Psychology class .  
 Person2:Well , there are only two classes open .  
 Person1:        Can you tell me what days the classes are on ?  
 Person2:One class is on Tuesday and Thursday from 2 p . m . to 4 .  
 Person1:        And the other class ?  
 Person2:That class is from ten to twelve on Monday and Wednesday .  
 Person1:        Are you sure these are the only open classes ?  
 Person2:Yes , I am sure .  
 Person1:        Okay , sign me up for the class on Monday and Wednesday .  
 Person2:Very well then . 

formal