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:       I ’ d like to take this opportunity to thank you for everything you did for me .  
 Person2:It ’ s my pleasure . I enjoyed working with you .  
 Person1:        I wouldn ’ t be able to make it without your help .  
 Person2:Then keep up the good work . 

informal