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:       Hi , I'm Benjamin . Nice to meet you here . You look great . 
 Person2:Thank you . Nice to meet you too . I'm John . Is this your first time to take a long-distance trip on plane . 
 Person1:        No , this is the second time . But I also feel bad because of the lower pressure and the jet lag . 
 Person2:Oh , I am sorry to hear that . Take it easy . It will be OK soon . You see , I take this long-hour plane frequently , but the jet lag still makes me uneasy . 
 Person1:        Oh , that's too bad . Do you get a good knowledge of China ? 
 Person2:Yes , whenever I think about China , I'd see the Tian'an Men Square . China is a very beautiful country . And I've seen many landmarks in China but I like the Great Wall most . 
 Person1:        All of the Chinese are proud of the Great Wall . And it was built before the In dynasty near Shan Haiguan-the First Pass in the World . 
 Person2:Was it built before the In dynasty ? I thought it was in the Ming dynasty . 
 Person1:        No , before the In dynasty . 
 Person2:Oh , yeah . Thought I am an American , I know quite a lot about China and I like Chinese tea very well . 
 Person1:        Both the green tea and the black tea are good for our health . And I usually refresh myself with a cup of tea . 

informal