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 mind if I use your tape-recorder ?  
 Person2:I don't mind . Go ahead .  
 Person1:        I'll give it back to you in a couple of days .  
 Person2:OK . You can keep it as long as you need . 

informal