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:       Would you like to go to a concert tonight ? 
 Person2:I'd like to very much . 
 Person1:        All right , then.There is one at the new concert hall . 
 Person2:Who's playing ? 
 Person1:        It's the Powell orchestra . 
 Person2:Do you know what they are playing ? 
 Person1:        They're doing a seventeenth-century program . 
 Person2:And who is directing ? 
 Person1:        Well , I'm not sure of his name , but I know it's going to be his farewell performance . 

formal