Define a period

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How many working days in year 1971?

Here is the detail of the calculation:

Because 1971 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 8 public holidays that do not fall during a weekend and we obtain 253 working days in 1971.

Here is the list of these 8 public holidays:

1. Nieuwjaarsdag : Friday, 1 January, 1971
2. Paasmaandag : Monday, 12 April, 1971
3. Hemelvaartsdag : Thursday, 20 May, 1971
4. Pinkstermaandag : Monday, 31 May, 1971
5. Nationale Feestdag : Wednesday, 21 July, 1971
6. Feest van de Franse Gemeenschap : Monday, 27 September, 1971
7. Allerheiligen : Monday, 1 November, 1971
8. Wapenstilstand : Thursday, 11 November, 1971

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

1. Dag van de Arbeid : Saturday, 1 May, 1971
2. Onze-Lieve-Vrouw Hemelvaart : Sunday, 15 August, 1971
3. Kerstmis : Saturday, 25 December, 1971