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:       What a good day !  
 Person2:Yes . It's really wonderful here The grass is greener and the air is fresher than those in the city .  
 Person1:        Right . Let's go out and enjoy the beautiful natural scenery .  
 Person2:Great , let's go .  
 Person1:        Wow , what a beautiful lake ! The green hills and clear water really provide magnificent scenery .  
 Person2:En , it's so beautiful that I don't want to move my eyes from it .  
 Person1:        I feel as if I'm living in a different world , honey .  
 Person2:The same to me . All the things here make me happy , the mountain , the water , the grass , the birds , the sunshine ...  
 Person1:        I think we should go out more frequently . The natural scenery can do us good .  
 Person2:That's the point . We should walk into the nature and enjoy its beauty whenever we have time .  
 Person1:        Right . The city life has made us tired and out of energy , while the natural world can bring us quite new feelings . 

informal