static void Main(string[] args)
{
double output;
List <double> numbers = new List <double>();
string[] inputs = Console.ReadLine().Replace('.', ',').Split(Separator);
int strlen = inputs.Length;
double tmp = 0;
for (int i = 0; i < strlen; i++)
{
if (inputs[i] != string.Empty)
{
if (!double.TryParse(inputs[i], out tmp))
{
continue;
}
numbers.Add(tmp);
}
}
double N = numbers.Count;
double x_carka;
tmp = 0;
for (int i = 0; i < N; i++)
{
tmp = OwnMath.add(tmp, numbers[i]);
}
x_carka = OwnMath.mul(OwnMath.div(1, N), tmp);
tmp = 0;
for (int i = 0; i < N; i++)
{
tmp = OwnMath.add(tmp, OwnMath.pow(numbers[i], 2));
}
output = OwnMath.sqrt(OwnMath.mul(OwnMath.div(1, OwnMath.sub(N, 1)), OwnMath.sub(tmp, OwnMath.mul(N, OwnMath.pow(x_carka, 2)))));
Console.WriteLine(output);
}
public void SubTest()
{
//check sub(double a, double b)
Assert.AreEqual(10, OwnMath.sub(15.5, 5.5));
Assert.AreEqual(-10, OwnMath.sub(-15.5, -5.5));
}