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:       Is there any ticket left for tonight's concert ?  
 Person2:I am sorry , sir.All the tickets have been sold out .  
 Person1:        What a shame . Will there be the same performance tomorrow evening ?  
 Person2:Sorry , sir . The only tickets of the same performance available are on 21st .  
 Person1:        That's fine . I want 2 tickets . 

formal