You will be given a definition of a task first, then some input of the task.
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'.

Person1: What's the weather like ?
Person2:I don't know . I just woke up .
Person1: Why don't you look outside ?
Person2:Okay . It looks like rain .
Person1: Why do you say that ?
Person2:The sky is gray .
Person1: Is it raining right now ?
Person2:No .
Person1: How do you know ?
Person2:The street isn't wet .
Person1: I have to go shopping today .
Person2:You'd better take an umbrella .
Output:
formal