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: Where are we going to visit today ?
Person2:We are going to the national park .
Person1: Really ? I have heard there are many famous national park in the US , which one exactly ?
Person2:The Yellow Rock National Park .
Person1: That's wonderful . I will see the Old Faithful for myself .
Output:
informal