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 you have any seat preferences , sir ? 
 Person2:Yes , could you put me in the non-smoking section ? 
 Person1:        Yes . Would you like a window seat ? 
 Person2:If one's available , please . But not over the wing . 

formal