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 do you think the transport system in our city could be improved ?  
 Person2:I think that the public transport system could be made simpler . I never know where the bus routes actually go . The routes seem to twist and turn rather than going roughly in a straight line .  
 Person1:        I think we just need to build more roads . Then there would be more space for cars to drive and we ’ d have fewer traffic jams .  
 Person2:If we built more roads , people would just fill them with cars again . I think we should discourage people from using their cars .  
 Person1:        How would you do that ?  
 Person2:I think we should do a few things at once . Improving public transport would encourage people to use that . If we also charge people to use their cars in the city centre , they won ’ t use their cars as much .  
 Person1:        I don ’ t know . I think it ’ s unfair to make drivers pay more money . They already pay a lot of tax-petrol tax , for example .  
 Person2:I think that they should pay more tax . Look at the damage they cause to the environment and people ’ s health by discharging all those exhaust fumes .  
 Person1:        The air would certainly be cleaner if there were fewer cars being used in the city . The problem is that people will see it as reducing their freedom . It well be unpopular .  
 Person2:That ’ s a good point . Car owners will probably be against it , but people who use public transport will be in favor of it . 

informal