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:       Well , humans could never make something like that .  
 Person2:Those poor Egyptians slaves worked so hard and you want to give aliens all the credit !  
 Person1:        Be a little more open-minded , Stu ! Don't believe everything you read in your history books !  
 Person2:OK , but don't believe everything you see on The X-files , either !  
 Person1:        Speaking of The X-files , it's on right now ! 

informal