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:       Will you have time this Saturday evening to go to the cinema with me ?  
 Person2:Saturday ? Oh , I have a previous engagement .  
 Person1:        What a pity ! Then how about Sunday ?  
 Person2:I've already got plans , too .  
 Person1:        Then when do you think we could go out together ?  
 Person2:How about Friday ? Only in that day can I arrange it .  
 Person1:        OK . Any time on Friday will be OK with me .  
 Person2:That's settled then . I'll contact you later . 

informal