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:       Merry Christmas ! Mary !  
 Person2:Merry Christmas ! Mr Bean .  
 Person1:        Will you come to join us at dinner this evening ? My family will be happy to see you . And father misses you very much .  
 Person2:Well , I would be glad to , but I have promised Tom to see his Christmas tree , and play the piano for his song tonight . 

informal