A day is called " Factor day '' if the month number times the day equals to the number formed by the last 2 digits of the year . For example, 2nd of September 2018 is a Factor day since 2 x 9 = 18, as well as 8th of February 2016 because 8 x 2 = 16 . How many Factor days are there from 1st of January 2015 to 31st of December 2019