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:       If you are staying here for a few days , we ’ d be delighted to see you at our factory .  
 Person2:It ’ s very kind of you to say so . My associate and I will be interested in visiting your factory .  
 Person1:        Let us know when you are free . We ’ ll arrange the tour for you .  
 Person2:Thank you . I ’ ll give you a call this afternoon to set the time . There ’ s nothing like seeing things with one ’ s own eyes .  
 Person1:        That ’ s for sure . You ’ ll know our products better after the visit . 

informal