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 , Kathy . Have you had lunch ?  
 Person1:        Not yet . And I ’ m really hungry now .  
 Person2:I ’ m starving , too . There is a new Chinese restaurant close by . Do you want to go there for lunch ?  
 Person1:        Why not ?  
 Person2:It ’ s my treat this time .  
 Person1:        Thanks . I could eat a cow . 

informal