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:       Hi , Bob . Can I have the book back I lent to you last month ?  
 Person2:Oh ! I forgot all about it . Of course you can have it back , John . I'm sorry about the delay .  
 Person1:        Well , it doesn't matter . I almost forgot it too if it is not for Peter who asked me about it this coming . 

informal