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:       How about the hiking ? It was freezing yesterday , are you all ok ? 
 Person2:Can ’ t be better , it was wonderful . We had a lot of fun there . There was so much joy and walk and breathe the winter air . We arrived at the park at 9 o ’ clock in the morning and didn ’ t leave till 3 o ’ clock in the afternoon . 
 Person1:        You had been walking for 6 hours , isn ’ t that boring ? 
 Person2:Of course not ! We built a snowman , some snow dogs and one big snow fort . We went sliding on the nice hill . It was a real work out . At noon , we had the most special winter picnic outside . Fortunately , we got it all on a video tape . You must come with us next time . I bet you will love it . 
 Person1:        Well . You know I hate walking , but I can ’ t wait to see your guys ’ video . 

informal