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:       Good morning , Japan Airline domestic reservations . Can I help you ?  
 Person2:Yes . I Would like make a reservation to Huston for tomorrow .  
 Person1:        The flight to Huston takes off daily every two hours from 6:00 to 11:00 pm . So you don't need a reservation . Seats are available on a ' first come , first served ' basis .  
 Person2:Oh , that's quite convenient . Thank you . 

informal