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:       Northwest Airline .  
 Person2:Hello , I'd like to reconfirm my flight .  
 Person1:        May I have your flight No . , PLS ?  
 Person2:My flight No . is 102 leaving Baiyun Airport at fourteen twenty .  
 Person1:        Yes , that's our regular flight to Shanghai . What's your name , PLS ?  
 Person2:I am Jason Armstrong . My first initial is J .  
 Person1:        One minute . Oh , yes , here we are . You are flying economy class , aren ’ t you ?  
 Person2:Yes , that's right .  
 Person1:        Okay , you are all set , Mr . Armstrong . Enjoy your flight !  
 Person2:Thanks ! 

formal