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:       Do you mind if I ask you to practice speaking English with me ?  
 Person2:No . Of course not . But what for ?  
 Person1:        Well , I'm meeting some American friends next weekend .  
 Person2:I see . But I'm busy now . How about tomorrow ? 

formal