dayOfWeek = (y + y/4 - y/100 + y/400 + (13*m + 8)/5 + d) mod 7

In this formula, "y" represents the year (for example, 2023), "m" represents the month (1 for January, 2 for February, and so on), and "d" represents the day of the month (for example, 25 for April 25, 2023).