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:       Why are those people crying ?  
 Person2:They must have just come back from tomb sweeping because today is Tomb Sweeping Day .  
 Person1:        Tomb Sweeping Day ? What is it ?  
 Person2:Tomb Sweeping Day is a traditional festival in China , on which many Chinese mourn the dead .  
 Person1:        What do they do ?  
 Person2:People go to the cemetery to pay their respects to the dead . 

formal