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:       Spring Festival is the most important festival in China , isn't it ?  
 Person2:Yes , that's true .  
 Person1:        How long is the holiday ?  
 Person2:It depends.But usually it's about 15 days .  
 Person1:        Do you eat any special food for the festival ?  
 Person2:Yes , dumpling is a must.There is also other food.For example , people eat chicken for good luck .  
 Person1:        That's interesting . I'm told the Chinese firework is very beautiful , isn't it ?  
 Person2:Yes , it's really wonderful !  
 Person1:        Oh , great ! I hope I can spend this Spring Festival with you here in Beijing .  
 Person2:I'm sure you'll have a good time . 

informal