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:       What do you think of his behaviour yesterday ?  
 Person2:He's a sad dog . He came to the wedding in jeans !  
 Person1:        I don't think so . He only had no common sense . 

informal