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:       Is that Mr . Green ?  
 Person2:This is him speaking .  
 Person1:        I am calling to inform you that we're happy to have you with us . Welcome aboard , I'm sure your friend would have given you a lot of information of our school and its motto , ways of teaching , etc .  
 Person2:Yes . I am very glad to have the chance . 

informal