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 happen , John ?  
 Person2:Nothing .  
 Person1:        Why do you look unhappy ?  
 Person2:I ’ m rather disappointed at not being able to see my best friend off .  
 Person1:        Oh , cheer up . He ’ ll understand you . 

informal