C#.NET - Find sum using class

Q. Write a Program to input 2 numbers and find sum using class in console C#.NET 1

class Sum
{
    int a, b, c;
    public void input()
    {
        Console.WriteLine("Enter 2 numbers:");
        a = Convert.ToInt32(Console.ReadLine());
        b = Convert.ToInt32(Console.ReadLine());
    }
    public void add()
    {
        c = a + b;
        Console.WriteLine("Sum = " + c);
    }
}
class Program
{
    static void Main(string[] args)
    {
        Sum s = new Sum();
        s.input();
        s.add();
        Console.ReadLine();
    }
}