public static void Main()
Console.WriteLine("Enter a number");
int n = Int32.Parse(Console.ReadLine());
string str = n.ToString();
char[] a = str.ToCharArray();
r = Int32.Parse(a[i].ToString()) - Int32.Parse(a[i + 1].ToString());
for (int i = 0; i < l - 1; i++)
r = Int32.Parse(a[i].ToString()) - Int32.Parse(a[i + 1].ToString());
Console.WriteLine("The output is = {0}", sum);