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 afternoon.Swiss Airline.Miss Grown speaking . Can I help you ?  
 Person2:Yes . I'd like to make a reservation to Los Angeles on Sep . 19th .  
 Person1:        Just a moment , please . Let me check for you . ( A moment later ) Thank you for waiting . I am sorry but our flights are fully booked on that day.The next available flight leaves at 4:00 pm on 20th . Shall I reserve you a seat on it ?  
 Person2:Yes , please , thank you . 

formal