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:       Welcome to China , Mr . Martin .  
 Person2:Thank you so much . I have been expecting to come to China .  
 Person1:        I am very glad that you say so . We have prepared a typical Chinese dinner this evening .  
 Person2:Oh , you needn't do that .  
 Person1:        My pleasure . 

informal