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 would like to make a reservation for tomorrow .
Person2:I'm sorry but we are fully booked .
Person1: Well , how about 4th ?
Person2:That's fine , but we have only a single room , is that OK ?
Person1: Yes . Please help me reserve it .
Output:
formal