using System;

​

public class Program

{

  const double MAX_SAFE_INT = 9007199254740991;

​

  public static void Main()

  {

    var rgn = new Random(Environment.TickCount);

    double random = rgn.NextDouble();

    double product = MAX_SAFE_INT * random;

    Console.WriteLine($"{MAX_SAFE_INT}, {random}, product: {product}");

    Decimal randomD = (Decimal)random;

    Decimal maxD = (Decimal)MAX_SAFE_INT;

    Decimal productD = maxD * randomD;

    Console.WriteLine($"{maxD}, {randomD}, product: {productD}, {(double)productD}");

  }

}