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:       Thank you for coming to see me off .  
 Person2:Not at all .  
 Person1:        If I have time , I will come again .  
 Person2:You are welcome at any time .  
 Person1:        Thank you for your hospitality . I hope I didn ’ t cause you too much trouble during my stay .  
 Person2:You are most welcome .  
 Person1:        I ’ m afraid I have to go now . The plane will take off soon .  
 Person2:Call us as soon as you got home . 

informal