Define a period

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How many working days in year 1977?

Here is the detail of the calculation:

Because 1977 is not a leap year, it has 365 days.

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

Now, let's remove 9 public holidays that do not fall during a weekend and we obtain 251 working days in 1977.

Here is the list of these 9 public holidays:

1. Sexta-Feira Santa : Friday, 8 April, 1977
2. Dia da Liberdade : Monday, 25 April, 1977
3. Corpo de Deus : Thursday, 9 June, 1977
4. Dia de Portugal : Friday, 10 June, 1977
5. Assunção de Nossa Senhora : Monday, 15 August, 1977
6. Implantação da República : Wednesday, 5 October, 1977
7. Todos os Santos : Tuesday, 1 November, 1977
8. Restauração da Independência : Thursday, 1 December, 1977
9. Dia da Imaculada Conceição : Thursday, 8 December, 1977

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

1. Solenidade da Santa Mãe de Deus : Saturday, 1 January, 1977
2. Páscoa : Sunday, 10 April, 1977
3. Dia do Trabalhador : Sunday, 1 May, 1977
4. Natal : Sunday, 25 December, 1977