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:       Sorry , I have to rush off and catch the 9 o'clock train to Paris . 
 Person2:Then you must hurry up.There ' s only ten minutes left . 
 Person1:        Until we meet again . 

informal