Define a period

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How many working days in year 1984?

Here is the detail of the calculation:

Because 1984 is a leap year, it has 366 days.

Let's remove 52 saturdays and 53 sundays. It remains 261 days.

Now, let's remove 12 public holidays that do not fall during a weekend and we obtain 249 working days in 1984.

Here is the list of these 12 public holidays:

1. New Year's Day (observance) : Monday, 2 January, 1984
2. Coming of Age Day : Monday, 9 January, 1984
3. Vernal Equinox Day : Tuesday, 20 March, 1984
4. Shōwa Day (observance) : Monday, 30 April, 1984
5. Constitution Memorial Day : Thursday, 3 May, 1984
6. Greenery Day : Friday, 4 May, 1984
7. Marine Day : Monday, 16 July, 1984
8. Respect-for-Aged Day : Monday, 17 September, 1984
9. Autumnal Equinox Day (observance) : Monday, 24 September, 1984
10. Health and Sports Day : Monday, 8 October, 1984
11. Labor Thanksgiving Day : Friday, 23 November, 1984
12. Emperor's Birthday (observance) : Monday, 24 December, 1984

And here are the 7 public holidays falling on a weekend:

1. New Year's Day : Sunday, 1 January, 1984
2. Foundation Day : Saturday, 11 February, 1984
3. Shōwa Day : Sunday, 29 April, 1984
4. Children's Day : Saturday, 5 May, 1984
5. Autumnal Equinox Day : Sunday, 23 September, 1984
6. Culture Day : Saturday, 3 November, 1984
7. Emperor's Birthday : Sunday, 23 December, 1984