public static void Main()
string entrada1 = Console.ReadLine();
string[] values1 = entrada1.Split(' ');
double x1 = double.Parse(values1[0]);
double y1 = double.Parse(values1[1]);
string entrada2 = Console.ReadLine();
string[] values2 = entrada2.Split(' ');
double x2 = double.Parse(values2[0]);
double y2 = double.Parse(values2[1]);
string distancia = (Math.Sqrt(Math.Pow((x2-x1),2)+Math.Pow((y2-y1),2))).ToString("#0.0000");
Console.WriteLine(distancia);