Define a period

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How many working days in year 1990?

Here is the detail of the calculation:

Because 1990 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 9 public holidays that do not fall during a weekend and we obtain 252 working days in 1990.

Here is the list of these 9 public holidays:

1. Solenidade da Santa Mãe de Deus : Monday, 1 January, 1990
2. Sexta-Feira Santa : Friday, 13 April, 1990
3. Dia da Liberdade : Wednesday, 25 April, 1990
4. Dia do Trabalhador : Tuesday, 1 May, 1990
5. Corpo de Deus : Thursday, 14 June, 1990
6. Assunção de Nossa Senhora : Wednesday, 15 August, 1990
7. Implantação da República : Friday, 5 October, 1990
8. Todos os Santos : Thursday, 1 November, 1990
9. Natal : Tuesday, 25 December, 1990

And here are the 4 public holidays falling on a weekend:

1. Páscoa : Sunday, 15 April, 1990
2. Dia de Portugal : Sunday, 10 June, 1990
3. Restauração da Independência : Saturday, 1 December, 1990
4. Dia da Imaculada Conceição : Saturday, 8 December, 1990