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:       Hello . I have left my key in my room . But I can't get in now . 
 Person2:May I have your name and room number ? 
 Person1:        I am Molopo and my room is 5022 . 
 Person2:OK.sir . Please go upstairs . Someone will open the door for you . 
 Person1:        Thanks a lot . 

formal