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:       Thank you for your visit to our company . I'd like to make an introduction for you . Is there anything in particular you'd like to know ?  
 Person2:Your company has a very good reputation , and I have been planning to visit it for a long time . What's the advantage of your factory over other plastics ones ?  
 Person1:        Our production speed is almost twice the industry-wide average . And we've already expanded the factory this year .  
 Person2:Could you tell me the cost of production per unit ?  
 Person1:        I'm not familiar with that part . Let me call someone in charge . 

formal