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 honor us with a visit ? 
 Person2:I'd love to . Thanks . 
 Person1:        When will you be convenient ? 
 Person2:Any time will suit me . 
 Person1:        Are you doing anything tomorrow ? 
 Person2:I'm free tomorrow . 
 Person1:        I'll pick you up at about nine o'clock , will it do ? 
 Person2:All right , see you then . 

informal