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 , is this People's Theater ? 
 Person2:Yes , it is . May I help you ? 
 Person1:        Yes , are advance tickets for ' Nut croakers ' still available ? 
 Person2:What date , sir ? 
 Person1:        October 16th . 
 Person2:Let me see . Yes , we still have some tickets left . Which performance ? 
 Person1:        7:30 p . m . performance , please . 
 Person2:OK , we have tickets at 100 yuan and 50 yuan . 
 Person1:        I'd like to reserve two seats at 100 yuan , please . 
 Person2:All right . May I have you name , please ? 
 Person1:        Du Kun . 
 Person2:When would you like to collect the tickets ? 
 Person1:        Tomorrow . 
 Person2:We can hold them until one day before the show . 
 Person1:        How do we cancel , just in case ? 
 Person2:Just telephone us , and let us know in advance . We don't charge for cancellation . 
 Person1:        All right , thank you very much . Good bye . 
 Person2:You are welcome . Goodbye . 

informal