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:       Let's go to the cinema tonight , shall we ?  
 Person2:Good idea . Is there a good movie on ?  
 Person1:        What about ' Farewell My Concubine ' ? I've been wanting to see it for a long time .  
 Person2:All right . But it'll be difficult to buy tickets I suppose .  
 Person1:        My brother has offered me two tickets for this evening .  
 Person2:What time does it begin ?  
 Person1:        At eight thirty .  
 Person2:I'll come for you at about eight .  
 Person1:        OK , I'll be waiting . 

informal