Define a period

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How many working days in year 1987?

Here is the detail of the calculation:

Because 1987 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 52 sundays. It remains 261 days.

Now, let's remove 7 public holidays that do not fall during a weekend and we obtain 254 working days in 1987.

Here is the list of these 7 public holidays:

1. Nieuwjaar : Thursday, 1 January, 1987
2. Goede Vrijdag : Friday, 17 April, 1987
3. Tweede Paasdag : Monday, 20 April, 1987
4. Koninginnedag : Thursday, 30 April, 1987
5. Hemelvaartsdag : Thursday, 28 May, 1987
6. Tweede Pinksterdag : Monday, 8 June, 1987
7. Eerste Kerstdag : Friday, 25 December, 1987

And here are the 3 public holidays falling on a weekend:

1. Eerste Paasdag : Sunday, 19 April, 1987
2. Eerste Pinksterdag : Sunday, 7 June, 1987
3. Tweede Kerstdag : Saturday, 26 December, 1987