Определить период

...

How many working days in year 1920?

Here is the detail of the calculation:

Because 1920 is a leap year, it has 366 days.

Let's remove 52 saturdays and 52 sundays. It remains 262 days.

Now, let's remove 7 public holidays that do not fall during a weekend and we obtain 255 working days in 1920.

Here is the list of these 7 public holidays:

1. Jour de l'An : четверг, 1 январь, 1920
2. Saint-Joseph : пятница, 19 март, 1920
3. Vendredi Saint : пятница, 2 апрель, 1920
4. Jeudi de l'Ascension : четверг, 13 май, 1920
5. Fête-Dieu : четверг, 3 июнь, 1920
6. Toussaint : понедельник, 1 ноябрь, 1920
7. Immaculée Conception : среда, 8 декабрь, 1920

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

1. Fête nationale suisse : воскресенье, 1 август, 1920
2. Assomption : воскресенье, 15 август, 1920
3. Noël : суббота, 25 декабрь, 1920