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:       Hi . I need a wake-up call tomorrow .  
 Person2:What time would you like your wake-up call ?  
 Person1:        I need two calls , one at 7 and another at 7 fifteen .  
 Person2:That is no problem at all , of course . You'll get a call at 7 o'colock and another at 7 fifteen .  
 Person1:        Then again , I think 7 fifteen is too early . Change 7 fifteen to 7 thirty , please .  
 Person2:So , that'll be a call at 7 and another at 7 thirty.Do you have any other requests ?  
 Person1:        Not just now , but if I do think of something later , I'll give you a ring .  
 Person2:Okay , sir . Sleep well . 

formal