The COVID-19 pandemic has led to shutdown of many businesses and high unemployment in the US. Meanwhile, surgical masks are in high demand. Suppose in this context, SM Inc., a producer of surgical masks, had managed to overcome the health hazard and continue its operations, producing $15 million worth of masks during first quarter of 2020 (2020Q1). It sold all its production in that quarter as well as $5 million worth of masks that it had in its inventory at the beginning of the year and that were produced in 2019. If the production cost of these inventory masks in 2019 was $4 million, how much did the activities of SM Inc. contribute to the GDP in 2020Q1? Please remember to explain your answer in detail in addition to providing the calculated answer.

(please provide proper explanation and written analysis)