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:       What can I do for you ?  
 Person2:Would you recommend some materials on the World War Two ?  
 Person1:        Have you found a particular item from the card catalogue ?  
 Person2:Yes , but I don't think they are enough for me .  
 Person1:        Oh , maybe you can find something from the New York Times , or the Washington Post during that period .  
 Person2:That's a good idea . Thanks a lot .  
 Person1:        You are welcome . 

informal