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:       I wonder if it is possible that we organize a dinner party for all the colleagues in our departments . They are working very hard these days . Maybe it is time for everybody to relax a little .  
 Person2:That is a good idea , I love it . What time do you think is convenient ?  
 Person1:        Well , what about this Thursday evening after we finish the weekly meeting ?  
 Person2:Ok , I will inform everybody when they come back from lunch . It has been a long time since we had the department dinner last time . I am sure they don ’ t want to miss it .  
 Person1:        I hope so . Let me know how many will come . Then I will book the restaurant . 

informal