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:       Would you please weight this letter for me ? 
 Person2:Well , it's a bit overweight . You must pay extra for it . 
 Person1:        How much ? 
 Person2:We demand a surcharge of 80 cents for it . 

formal