Función Multiply & MultiplyR Ejercicio C# - Curso de Programación C# (C Sharp)

using System;
public class exercise133
{
    public static int MultiplyR(int n1, int n2)
    {
        if (n2 == 0)
            return 0;
        else
            return n1 + MultiplyR(n1, n2 - 1);
    }

    public static int Main(string[] args)
    {
        if (args.Length != 2)
        {
            Console.WriteLine("Enter two numbers!!");
            return 1;
        }
        else
        {
            int n1 = Convert.ToInt32(args[0]);
            int n2 = Convert.ToInt32(args[1]);

            Console.WriteLine(MultiplyR(n1, n2));
            return 0;
        }
    }
}