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:       Do I check in for the train D8 08 to Shanghai here ? 
 Person2:Yes , show me your tickets please . 
 Person1:        Here you are . By the way , when does the train leave ? 
 Person2:The train is driving after ten minutes . 
 Person1:        Thanks . Where is my seat ? 
 Person2:It's over there . Have a good trip . 
 Person1:        Thank you . 

informal