Write a program that prints to the console which day of the week is
today. Use System.DateTime.
Write methods that calculate the surface of a triangle by given:
- Side and an altitude to it;
- Three sides;
- Two sides and an angle between them.
Use System.Math.
Write a method that calculates the number of workdays between today and
given date, passed as parameter.
Consider that workdays are all days from Monday to Friday except a fixed
list of public holidays  specified preliminary as array.
You are given a sequence of positive integer values written into a
string, separated by spaces.
Write a function that reads these values from given string and
calculates their sum.
Example:    string = "43 68 9 23 318" -> result = 461