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:       Hello . I would like to make a reservation at 8: 00 . 
 Person2:OK , sir . How many are coming ? 
 Person1:        4 . By the way , what's your dress code ? 
 Person2:We require a jacket and tie . 
 Person1:        I see . Thank you . 

informal