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:       Anything interesting in this city ? 
 Person2:We have a beautiful natural park . 
 Person1:        It's worth the time . 
 Person2:Come on.Let ' s walk there . 

formal