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 think the bad weather will last long ? 
 Person2:I don't think so . It changes so quickly this time . 
 Person1:        I hope so . We have planed to visit the square but we have to cancel it . 
 Person2:I think you can go to visit the museum . It's worth seeing . You can go to the square some other time . 
 Person1:        Good idea . Thanks a billion . 

informal