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:       What ’ s the date today ?  
 Person2:December the fifteenth . The day after tomorrow is little Tom ’ s birthday .  
 Person1:        Right . What present should we give him this time ? By the way , how old is he ?  
 Person2:Thirteen today and tomorrow . Fourteen the day after tomorrow .  
 Person1:        How time flies ! He ’ s a big boy now .  
 Person2:And don ’ t forget Mary , Tom ’ s twin sister . It ’ s her birthday , too .  
 Person1:        OK . Let ’ s invite all their little friends to come and celebrate . 

formal