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 6 public holidays that do not fall during a weekend and we obtain 256 working days in 1920.

Here is the list of these 6 public holidays:

1. New Year's Day : четверг, 1 январь, 1920
2. Good Friday : пятница, 2 апрель, 1920
3. Easter Monday : понедельник, 5 апрель, 1920
4. Establishment Day : четверг, 1 июль, 1920
5. National Day : пятница, 1 октябрь, 1920
6. Boxing Day : понедельник, 27 декабрь, 1920

And here are the 4 public holidays falling on a weekend:

1. Holy Saturday : суббота, 3 апрель, 1920
2. Labour Day : суббота, 1 май, 1920
3. Christmas Day : суббота, 25 декабрь, 1920
4. Boxing Day : воскресенье, 26 декабрь, 1920