Add two values without help of constructor in c# programming

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication6
{
    class Program
    {

         public static void Main(string[] args)
        {
            Add obj1 = new Add();
            obj1.StoreData(5, 6);
            int Sum = obj1.GetSum();
           Console.WriteLine(Sum);
           Console.ReadKey();
         }
    }
    class Add
    {

        public int a, b;
        public void StoreData(int x, int y)
        {
            a = x;
            b = y;
        }
        public int GetSum()
        {
            return (a + b);

        }
    }
}