What is the MinusOne field of decimal in C#?

// use System
using System;
// create class
class HelloWorld
{   
    static void Main()
    {
        // print the field
        Console.WriteLine(Decimal.MinusOne);
        // create decimal values
        decimal decimalNumberOne = Decimal.MinusOne;
        decimal decimalNumberTwo = 3.4m + Decimal.MinusOne;
        decimal decimalNumberThree = 10.00m / Decimal.MinusOne;
        // print values  
        Console.WriteLine(decimalNumberOne);
        Console.WriteLine(decimalNumberTwo);
        Console.WriteLine(decimalNumberThree);
    }
}