Define a period

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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 7 public holidays that do not fall during a weekend and we obtain 255 working days in 1980.

Here is the list of these 7 public holidays:

1. Uudenvuodenpäivä : Tuesday, 1 January, 1980
2. Pitkäperjantai : Friday, 4 April, 1980
3. 2. pääsiäispäivä : Monday, 7 April, 1980
4. Vappu : Thursday, 1 May, 1980
5. Helatorstai : Thursday, 15 May, 1980
6. Joulupäivä : Thursday, 25 December, 1980
7. Tapaninpäivä : Friday, 26 December, 1980

And here are the 6 public holidays falling on a weekend:

1. Loppiainen : Sunday, 6 January, 1980
2. Pääsiäispäivä : Sunday, 6 April, 1980
3. Helluntaipäivä : Sunday, 25 May, 1980
4. Juhannuspäivä : Saturday, 21 June, 1980
5. Pyhäinpäivä : Saturday, 1 November, 1980
6. Itsenäisyyspäivä : Saturday, 6 December, 1980