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:       Excuse me . Where can I buy some cigarettes ?  
 Person2:There is a shop on the ground floor . It sells both Chinese and foreign cigarettes .  
 Person1:        Can I also get some souvenirs there ?  
 Person2:Yes , sir . There is a counter selling all kinds of souvenirs  
 Person1:        By the way , where is the men's room ?  
 Person2:There is one at the end of the corridor .  
 Person1:        Thank you .  
 Person2:You are welcome . 

informal