Определить период

...

How many working days in year 1990?

Here is the detail of the calculation:

Because 1990 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 11 public holidays that do not fall during a weekend and we obtain 250 working days in 1990.

Here is the list of these 11 public holidays:

1. New Year's Day : понедельник, 1 январь, 1990
2. National Day : четверг, 15 март, 1990
3. Good Friday : пятница, 13 апрель, 1990
4. Easter Monday : понедельник, 16 апрель, 1990
5. Labour Day : вторник, 1 май, 1990
6. Pentecost Monday : понедельник, 4 июнь, 1990
7. State Foundation Day : понедельник, 20 август, 1990
8. National Day : вторник, 23 октябрь, 1990
9. All Saints' Day : четверг, 1 ноябрь, 1990
10. Christmas Day : вторник, 25 декабрь, 1990
11. Second Day of Christmas : среда, 26 декабрь, 1990

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

1. Easter Sunday : воскресенье, 15 апрель, 1990
2. Pentecost Sunday : воскресенье, 3 июнь, 1990