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:       This city is far too polluted . We should do something about it .  
 Person2:I agree . We need to recycle our trash and use public transportation more often . 

informal