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 8 public holidays that do not fall during a weekend and we obtain 254 working days in 1980.

Here is the list of these 8 public holidays:

1. New Year's Day : вторник, 1 январь, 1980
2. Easter Monday : понедельник, 7 апрель, 1980
3. Labour Day : четверг, 1 май, 1980
4. Corpus Christi : четверг, 5 июнь, 1980
5. Assumption of Mary : пятница, 15 август, 1980
6. Independence Day : вторник, 11 ноябрь, 1980
7. Christmas Day : четверг, 25 декабрь, 1980
8. Boxing Day : пятница, 26 декабрь, 1980

And here are the 5 public holidays falling on a weekend:

1. Epiphany : воскресенье, 6 январь, 1980
2. Easter Sunday : воскресенье, 6 апрель, 1980
3. Constitution Day : суббота, 3 май, 1980
4. Pentecost Sunday : воскресенье, 25 май, 1980
5. All Saints' Day : суббота, 1 ноябрь, 1980