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:       Hi , I'd like to return this radio .  
 Person2:All right . Do you have the receipt ?  
 Person1:        Here it is .  
 Person2:May I ask why you're returning the radio ?  
 Person1:        It does not work very well .  
 Person2:Would you like to exchange it ?  
 Person1:        No . I'd just like a refund .  
 Person2:Certainly . This will take only a few seconds . 

formal