Define a period

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How many working days in year 2015?

Here is the detail of the calculation:

Because 2015 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 13 public holidays that do not fall during a weekend and we obtain 248 working days in 2015.

Here is the list of these 13 public holidays:

1. New Year's Day : Thursday, 1 January, 2015
2. Coming of Age Day : Monday, 12 January, 2015
3. Foundation Day : Wednesday, 11 February, 2015
4. Shōwa Day : Wednesday, 29 April, 2015
5. Greenery Day : Monday, 4 May, 2015
6. Children's Day : Tuesday, 5 May, 2015
7. Marine Day : Monday, 20 July, 2015
8. Respect-for-Aged Day : Monday, 21 September, 2015
9. Autumnal Equinox Day : Wednesday, 23 September, 2015
10. Health and Sports Day : Monday, 12 October, 2015
11. Culture Day : Tuesday, 3 November, 2015
12. Labor Thanksgiving Day : Monday, 23 November, 2015
13. Emperor's Birthday : Wednesday, 23 December, 2015

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

1. Vernal Equinox Day : Saturday, 21 March, 2015
2. Constitution Memorial Day : Sunday, 3 May, 2015