Define a period

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How many working days in year 1957?

Here is the detail of the calculation:

Because 1957 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 10 public holidays that do not fall during a weekend and we obtain 251 working days in 1957.

Here is the list of these 10 public holidays:

1. Restoration Day of the Independent Czech State : Tuesday, 1 January, 1957
2. Good Friday : Friday, 19 April, 1957
3. Easter Monday : Monday, 22 April, 1957
4. Labour Day : Wednesday, 1 May, 1957
5. Liberation Day : Wednesday, 8 May, 1957
6. St Cyril and Methodius' Day : Friday, 5 July, 1957
7. Independence Day : Monday, 28 October, 1957
8. Christmas Eve : Tuesday, 24 December, 1957
9. Christmas Day : Wednesday, 25 December, 1957
10. St. Stephen's Day : Thursday, 26 December, 1957

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

1. Jan Hus Day : Saturday, 6 July, 1957
2. St Wenceslas Day : Saturday, 28 September, 1957
3. Freedom and Democracy Day : Sunday, 17 November, 1957