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 did you do over the weekend ?  
 Person2:I went a global warming rally in London . It was fantastic to be around so many people who care about the environment .  
 Person1:        do you think there's anything we can do to reverse the damage that's been done already ?  
 Person2:it might not be possible to fix the problems that we've created for ourselves , but there are lots of things we can do to prevent more damages from happening .  
 Person1:        like what ?  
 Person2:well , we can use public transport instead of taking our cars for a start .  
 Person1:        what else can we do to protect the environment ?  
 Person2:if you do have to drive , you should make sure that your car runs on unleaded petrol . Also , your home should use sources of renewable energy .  
 Person1:        how about recycling ? Does that actually help ?  
 Person2:yes . You should take your glass , paper , plastic , cardboard , and tin cans to a recycling center .  
 Person1:        what do you think is the biggest worry for our future ?  
 Person2:I think that the issue of greatest concern is having enough sources of clean water for everyone .  
 Person1:        I had no idea you were such as environmentalist before !  
 Person2:to be honest , in order for the earth to continue to be a habitable place , we're all going to have to become more interested in the environment . 

informal