Detailed Instructions: 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'.
Problem: Person1: You look so happy , Anna . Any good news ?
Person2:Yes . I ' Ve won the first prize in the math contest .
Person1: Really ? Congratulations !
Person2:Thank you , Paul .
Person1: By the way , would you like to have dinner with me tomorrow evening ? Tomorrow is my birthday .
Person2:Good , happy birthday to you !
Person1: Not so soon . It ' s not my birthday today . Well , you ' ll come , won ' t you ?
Person2:Sure , I will . Thank you for inviting me .
Person1: My pleasure .
Solution:
informal