Определить период

...

How many working days in year 1987?

Here is the detail of the calculation:

Because 1987 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 12 public holidays that do not fall during a weekend and we obtain 249 working days in 1987.

Here is the list of these 12 public holidays:

1. Confraternização Universal : четверг, 1 январь, 1987
2. Terça-feira de Carnaval : вторник, 3 март, 1987
3. Dia de São José : четверг, 19 март, 1987
4. Data magna do estado Ceará : среда, 25 март, 1987
5. Sexta Feira Santa ou Paixão de Cristo : пятница, 17 апрель, 1987
6. Tiradentes : вторник, 21 апрель, 1987
7. Dia do Trabalho : пятница, 1 май, 1987
8. Corpus Christi : четверг, 18 июнь, 1987
9. Independência do Brasil : понедельник, 7 сентябрь, 1987
10. Nossa Senhora Aparecida : понедельник, 12 октябрь, 1987
11. Finados : понедельник, 2 ноябрь, 1987
12. Natal : пятница, 25 декабрь, 1987

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

1. Criação do Território Federal : воскресенье, 13 сентябрь, 1987
2. Proclamação da República Brasileira : воскресенье, 15 ноябрь, 1987