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:       May I invite you to dance with me ?  
 Person2:Sorry , I can't dance .  
 Person1:        Never mind , I can teach you .  
 Person2:Is it difficult to learn ?  
 Person1:        No , it is easy .  
 Person2:How should I do ?  
 Person1:        You just follow me .  
 Person2:All right . By the way , do you often dance ?  
 Person1:        Yup , because dance can relax myself .  
 Person2:It seems a good way . 

informal