Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. If the conversation begins with a question, label it '1' otherwise '0'.
Input:  Person1:     Excuse me , are you Dr . Smith ?  
 Person2:  Yes I am . And you ...  
 Person1:      I'm David , Joanna's husband . She has to be at work late today . So she asked me to pick you up here .  
 Person2:  So nice to meet you , David . Call me Bill . It's very nice of you to come here .  
 Person1:      My pleasure . 

1