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:       David , I ’ m going to China .  
 Person2:Really ? How do you get the chance ?  
 Person1:        You know . I took part in the Chinese contest . I was the best and they gave me this reward . I don ’ t have to pay for my trip .  
 Person2:Congratulations . How lucky you are !  
 Person1:        Thank you . I ’ m leaving tomorrow morning .  
 Person2:I ’ m sure you ’ ll enjoy the trip . China is such a beautiful country .  
 Person1:        I ’ m sure I will .  
 Person2:Have a nice journey , Lily .  
 Person1:        Thank you , David . 

informal