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:       Good evening Ms . Jackson . Fancy meeting ’ you here .  
 Person2:Hi , Clyde . This is my friend , Wen . She's visiting from UCLA .  
 Person1:        Clyde Smith . Pleasure to meet you . May I treat you ladies to dinner ?  
 Person2:OK ! I was just tellin ’ Wen about African-American food .  
 Person1:        You weren't going to tell her about chitterlings and hog maws , were you ? Well , my Creole ancestors never ate that stuff . We have refined French tastes .  
 Person2:Hey ! That “ stuff ” is my grandma's cooking , and it's good ! 

informal