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:       I'm calling to say good-bye .  
 Person2:When do you leave ?  
 Person1:        I'm catching the eleven o'clock train .  
 Person2:Take care of yourself and don't forget to keep in touch .  
 Person1:        Goodbye . Thanks again for everything . 

informal