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:       What can I do for you , madam ?  
 Person2:I'd like to buy a toy car for my son .  
 Person1:        How about this one ?  
 Person2:It looks nice.How much is it ?  
 Person1:        They're three hundred dollars .  
 Person2:Oh , I'm afraid it's too expensive.Can you show me something cheaper ?  
 Person1:        OK , This one is one hundred and twenty.It ' s the cheapest here .  
 Person2:OK , I'll take it.Here ' s the money .  
 Person1:        Thank you very much . 

informal