Определить период

...

How many working days in year 1980?

Here is the detail of the calculation:

Because 1980 is a leap year, it has 366 days.

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

Now, let's remove 11 public holidays that do not fall during a weekend and we obtain 251 working days in 1980.

Here is the list of these 11 public holidays:

1. New Year's Day : вторник, 1 январь, 1980
2. Human Rights Day : пятница, 21 март, 1980
3. Good Friday : пятница, 4 апрель, 1980
4. Family Day : понедельник, 7 апрель, 1980
5. Freedom Day observance : понедельник, 28 апрель, 1980
6. Workers' Day : четверг, 1 май, 1980
7. Youth Day : понедельник, 16 июнь, 1980
8. Heritage Day : среда, 24 сентябрь, 1980
9. Day of Reconciliation : вторник, 16 декабрь, 1980
10. Christmas Day : четверг, 25 декабрь, 1980
11. Day of Goodwill : пятница, 26 декабрь, 1980

And here are the 2 public holidays falling on a weekend:

1. Freedom Day : воскресенье, 27 апрель, 1980
2. National Women's Day : суббота, 9 август, 1980