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:       Excuse me , do you have a vacancy ? 
 Person2:Let me see . Yes , we still have four left . 
 Person1:        Well , I would like to book a single room . 
 Person2:How long would you stay ? 
 Person1:        5 days . From Feb . 13 to 18 . 

formal