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:       Can I trouble you for some change ?  
 Person2:I'll see what I have got . What's it for ?  
 Person1:        I need some cigarettes .  
 Person2:I can let you have some silvers if that is good .  
 Person1:        OK , thanks . 

informal