addition of two numbers without using + operator

using System;

namespace example
{
    class Program
    {
        static void Main(string[] args)
        {
            int num1, num2;

           //Take input from user
            Console.WriteLine("Enter a Number");
            num1=Convert.ToInt16(Console.ReadLine());

            Console.WriteLine("Enter a Number");
            num2 = Convert.ToInt16(Console.ReadLine());

            int sum = num1 - ~num2 - 1;
            Console.WriteLine(sum);
        }
    }
}

Algorithm:

In Data structure ~ is 1's complement operator. This is equivalent to:  

~a = -b + 1

So, a - ~b -1

= a-(-b + 1) + 1

= a + b – 1 + 1

= a + b