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'm afraid I've got to go . I have another appointment at five .
Person2:Do you ? By the way , could you mail this letter for me as you go through the lobby ?
Person1: No problem .
Person2:Thank you . Come back to my office at the same time tomorrow . I'll have the pictures ready by then .
Person1: I will .
Output:
informal