How to find the second largest number of the given 0 to 9 numbers in c#

using System;

namespace Example

{

    class SecondLargestNum

    {

        static void Main()

        {

            int largeNum = 0;

            int smallNum = 0;

            Console.WriteLine("Enter the numbers");

            int num = int.Parse(Console.ReadLine());

            while (num > 0)

            {

                var mod = num % 10;

                if (mod > largeNum)

                {

                    smallNum = largeNum;

                    largeNum = mod;

                }

                if (mod != largeNum && smallNum < mod)

                {

                    smallNum = mod;

                }

                num = num / 10;

            }

            Console.WriteLine("Second largest number {0}: ", smallNum);

            Console.ReadLine();

        }

    }

} 

Output: