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:       Yes , ma'ma . May I help you with your bags ?  
 Person2:Oh , yes , if you like.The large one goes to Washington.The other one I will take with me . All right ?  
 Person1:        Flight 36 to Washington.It ' ll be on the plane for you .  
 Person2:Oh , thank you . Thank you very much . 

informal