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:       What do you think of your teacher ?  
 Person2:He's very strict with us .  
 Person1:        And I hear he gives very good lectures .  
 Person2:Indeed . He's strict with himself , too . We can see every lecture of his is well-prepared . 

informal