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:       The air quality in this city is horrendous . The pollution levels are so high that we are not supposed to go outside with a face mask again !  
 Person2:Exhaust fumes from vehicles cause a great deal of damage to the environment .  
 Person1:        On top of that , there are a few large chemical factories in the suburbs , which are contributing to the high pollution levels in the water and the air in this city .  
 Person2:As much as I love this city , I think I'm going to find a greener city to live in . Living in a polluted city like this just can't be good for my health .  
 Person1:        I know what you mean . However , there are so few places left that have not been affected by global warming . If it's not the pollution , then it's the natural disasters , deforestation , or the greenhouse effect .  
 Person2:What is the greenhouse effect exactly ?  
 Person1:        It's the gradual rise in the earth's temperature .  
 Person2:I see , so it's similar to global warming ?  
 Person1:        They're related to one another , yes .  
 Person2:I heard that some people in England are pleased with the fact that the climate is becoming warmer because it's making their towns a more pleasant place to live .  
 Person1:        People joke about the benefits of the increase in temperature , but it's not all good news . They've been experiencing a lot of deadly storms there as well .  
 Person2:People always seem to make jokes as a way to deal with unfortunate situations .  
 Person1:        I think if everyone pitches in , the world will be a better place . 

formal