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:       Do you know about All Fools ' Day ?  
 Person2:On that day , people play all kinds of tricks on others , and the one easily taken in is called April fool .  
 Person1:        April fool !  
 Person2:April the first is coming.Be careful ! 

formal