Define a period

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How many working days in year 2090?

Here is the detail of the calculation:

Because 2090 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 53 sundays. It remains 260 days.

Now, let's remove 11 public holidays that do not fall during a weekend and we obtain 249 working days in 2090.

Here is the list of these 11 public holidays:

1. Seollal / Korean New Year Holiday : Monday, 30 January, 2090
2. Seollal / Korean New Year Holiday : Tuesday, 31 January, 2090
3. 삼일절 : Wednesday, 1 March, 2090
4. 어린이날 : Friday, 5 May, 2090
5. 현충일 : Tuesday, 6 June, 2090
6. 광복절 : Tuesday, 15 August, 2090
7. 추석 : Thursday, 7 September, 2090
8. 추석 : Friday, 8 September, 2090
9. 개천절 : Tuesday, 3 October, 2090
10. 추석 : Monday, 9 October, 2090
11. 성탄절 : Monday, 25 December, 2090

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

1. 신정 : Sunday, 1 January, 2090
2. Seollal / Korean New Year Holiday : Sunday, 29 January, 2090
3. 석가탄신일 : Sunday, 7 May, 2090
4. 추석 : Saturday, 9 September, 2090
5. 추석 : Saturday, 7 October, 2090
6. 추석 : Sunday, 8 October, 2090