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:       Did your eye doctor prescribe you contact lenses ? 
 Person2:No , I ’ d like to know something about contact lenses . 
 Person1:        Oh , I see . We have both hard and soft contact lenses . They are very popular , but a little more expensive than ordinary glasses . 
 Person2:I have found I ’ m short-sighted recently . I need to wear glasses . As a student , it ’ s better for me to wear ordinary glasses instead of contact lenses . 
 Person1:        We have many kinds of glasses here . Which frames do you like best ? 
 Person2:I think the square-shaped ones will be the best for me . 
 Person1:        What about this pair ? They are the ' in ' things now in optical wear . Try them on . 
 Person2:They fit me very well . I like them . 
 Person1:        Please go to receive optometry first over there . 

informal