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:       My stay is over . Here's the key to my room .  
 Person2:Thank you . And here's your receipt , sir .  
 Person1:        Many thanks .  
 Person2:I hope your stay here was satisfactory , sir .  
 Person1:        This could be a great hotel , once you get rid of the insects . The city itself is great .  
 Person2:I'm glad that the little problem didn't ruin your visit . Please have a pleasant trip home . 

informal