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'.
Q: Person1: Today is the old couple ' s golden wedding .
Person2:That must be a long love story .
Person1: Yeah . They promised to stick together forever when they were young .
Person2:They have made it . Will our love last 50 years ?
Person1: I don ' t know .
A:
formal