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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 9 public holidays that do not fall during a weekend and we obtain 253 working days in 1980.

Here is the list of these 9 public holidays:

1. New Year's Day : вторник, 1 январь, 1980
2. New Year's Holiday : среда, 2 январь, 1980
3. Orthodox Christmas Day : понедельник, 7 январь, 1980
4. National Day : пятница, 15 февраль, 1980
5. Great Friday : пятница, 4 апрель, 1980
6. Easter Monday : понедельник, 7 апрель, 1980
7. May Day : четверг, 1 май, 1980
8. May Day Holiday : пятница, 2 май, 1980
9. Armistice Day : вторник, 11 ноябрь, 1980

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

1. National Day Holiday : суббота, 16 февраль, 1980
2. Orthodox Easter Saturday : суббота, 5 апрель, 1980
3. Easter : воскресенье, 6 апрель, 1980