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 ?  
 Person2:Hi , Shelley . Have you had lunch ?  
 Person1:        Not yet .  
 Person2:So shall we have lunch together ? I ’ d like to take you this time .  
 Person1:        I ’ d like to , but I can ’ t .  
 Person2:How come ?  
 Person1:        I ’ Ve a lot of paper work to do right now . I ’ m behind schedule .  
 Person2:All right . Can we make it another time ?  
 Person1:        Sure , thanks .  
 Person2:I ’ ll call you later . Bye .  
 Person1:        Bye . 

informal