Console.Write("Въведете x1: ");
double x1 = double.Parse(Console.ReadLine());
Console.Write("Въведете y1: ");
double y1 = double.Parse(Console.ReadLine());
Console.Write("Въведете x2: ");
double x2 = double.Parse(Console.ReadLine());
Console.Write("Въведете y2: ");
double y2 = double.Parse(Console.ReadLine());
double duljina = Math.Abs(x2 - x1);
double visochina = Math.Abs(y2 - y1);
double lice = duljina * visochina;
double perimeter = 2 * (duljina + visochina);
Console.WriteLine(perimeter);