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:       Hello , Zhang lin ! Fancy meeting you here !  
 Person2:Hi , Lin Tao . I have't seen you for some time .  
 Person1:        How's life going , Zhang Lin ?  
 Person2:Yes , the same as ever , thanks . What about you ?  
 Person1:        Pretty good , thanks . I'm going to see my uncle .  
 Person2:Good bye then , and keep in touch .  
 Person1:        Good bye . 

informal