Operator Overloading C#

using System;

public class Program
{
    public class Sample
    {
        public int a,b;
        public Sample(){a=0;b=0;} //Constructor
        public Sample(int A, int B){a=A;b=B;} //Constructor

        public static Sample operator +(Sample ob1, Sample ob2) // Operator overloading
        {
            Sample ob3= new Sample();
            ob3.a = ob1.a + ob2.a;
            ob3.b = ob1.b + ob2.b;
            return ob3;
        }
    }

    public static void Main()
    {
        Sample ob = new Sample(10,11);
        Sample ob1 = new Sample(20,21);
        Sample ob2 = new Sample();
        ob2 = ob1+ob;
        Console.WriteLine("ob2.a = "+ ob2.a);
        Console.WriteLine("ob2.b = "+ ob2.b);
    }
}