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 matter ?
Person2:Which subway should I take to get to the East Side ?
Person1: Oh , you have to take the shuttle to Grand Central .
Person2:Which train is that ? Which platform does it leave from ?
Person1: It's not on this platform.These trains are uptown and downtown , not crosstown.You have to go up these stairs over there .
Output:
formal