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:       Have any plans for the weekend , Tom ? 
 Person2:Yes . I am going for a hike around the Qinghai Lake . 
 Person1:        Oh , do you go hiking often ? 
 Person2:I go as much as I can . I love hiking , because you can really get in touch with nature . 
 Person1:        It would be nice to get out of the city . Do you want some company ? 
 Person2:Sure . But it will be a long hike 30 miles in three days . Have you been hiking before ? 
 Person1:        Yeah , I go a lot too . I saw a bear and a lion on my last hike . 
 Person2:Wow . You must have been pretty far away from the city . 
 Person1:        Yeah , my friend and I hiked in a very wild part of the national forest . 
 Person2:Well , bring him along to . We will have a great time this weekend . 
 Person1:        Thanks . I will ask him . 

formal