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:       Hello .  
 Person2:Hello.May I speak to Mark , please ?  
 Person1:        Sure , just a minute.Mark , you're wanted on the phone .  
 Person2:Hello , this is Mark speaking .  
 Person1:        Hi ! This is Jill.How come you didn't come in today ?  
 Person2:Oh , we had a birthday party for David last night . As a matter of fact I woke up with a terrible hangover .  
 Person1:        That's too bad.You ' ll have to be more careful nest time .  
 Person2:Anything new at the office ?  
 Person1:        No , nothing special.Oh , yes , you know Bill , The guy with the moustache.His wife had a baby girl last night and he passed out cigars to everyone today , He said his wife and daughter are doing fine.The baby is their first child .  
 Person2:That's wonderful ! We've got to celebrate !  
 Person1:        Yes , we have to.Do you think you can make it tomorrow ?  
 Person2:Sure . I ought to be ready for some more drinks by then.Thank you for calling .  
 Person1:        You're welcome.Bye . 

informal