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: Wang , I'd like you to meet my friend . Dou , this is Wang .
Person2:Hello Wang . I'm Dou . Pleased to meet you .
Person1: Pleased meet you , too , Mr . Dou .
Person2:Just call me Miao Dou , Please .
Output:
informal