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 don't we Chinese have our own Valentine's Day ?  
 Person2:Of course we have . It's on the seventh day of the seventh lunar month .  
 Person1:        Oh ? Why is that day ?  
 Person2:It is said that the Cowherd and the Spinster , the lover stars in heaven , can only meet on the seventh Eve , so this day has become the Lover's Day . 

formal