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 . 

informal