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:       Hey , let's go to the night market after work tonight . 
 Person2:That's a good idea . I haven't been in a while and I need to get a new backpack . The old one is hanging on by a thread ! 
 Person1:        That reminds me I should buy some new socks to go hiking this weekend . 

informal