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 , could you arrange a dinner for us ?  
 Person2:Sure , what time ?  
 Person1:        Eight o'clock tomorrow evening .  
 Person2:For how many people ?  
 Person1:        Ten .  
 Person2:Western food or Chinese food ?  
 Person1:        Chinese food .  
 Person2:Do you want an expensive meal ?  
 Person1:        No , not too lavish .  
 Person2:How much would you like to spend for each person ?  
 Person1:        What is the usual thing here ?  
 Person2:Forty to eighty RIB Yuan a plate .  
 Person1:        Let's say sixty Yuan then .  
 Person2:OK . Is there anything special you'd like to have on the menu ?  
 Person1:        We'd like to have typical Chinese food .  
 Person2:Anything you'd rather not have ?  
 Person1:        No snakes , please .  
 Person2:How about drinks ?  
 Person1:        Mao Tai and Qingdao Beer .  
 Person2:Well . Dinner for ten at sixty Yuan a plate , drink's extra , at 8 o'clock tomorrow evening . Is that all right ?  
 Person1:        Right , thanks .  
 Person2:My pleasure , see you tomorrow evening .  
 Person1:        See you then . 

informal