static double rectangle(double a, double b)
public static void Main()
double a = double.Parse(Console.ReadLine());;
double b = double.Parse(Console.ReadLine());;
double a1 = double.Parse(Console.ReadLine());;
double b1 = double.Parse(Console.ReadLine());;
double a2 = double.Parse(Console.ReadLine());;
double b2 = double.Parse(Console.ReadLine());;
double a3 = double.Parse(Console.ReadLine());;
double b3 = double.Parse(Console.ReadLine());;
double a4 = double.Parse(Console.ReadLine());;
double b4 = double.Parse(Console.ReadLine());;
Console.WriteLine(rectangle(a, b));
Console.WriteLine(rectangle(a1, b1));
Console.WriteLine(rectangle(a2, b2));
Console.WriteLine(rectangle(a3, b3));
Console.WriteLine(rectangle(a4, b4));