Crooked_Digits

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

namespace CrookedDigits
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            int sum = 0;
            List<string> list = new List<string>();

            foreach (var item in input)
            {
                list.Add(item.ToString());
            }
            if (list.Contains('.'.ToString()))
            {
                list.Remove('.'.ToString());
            }
            if (list.Contains('-'.ToString()))
            {
                list.Remove('-'.ToString());
            }

            List<int> result = list.Select(int.Parse).ToList();
            foreach (var item in result)
            {
                sum += item;
            }

            if (sum > 9)
            {
                while (sum > 9)
                {
                    string sumAsStr = sum.ToString();
                    List<int> newList = new List<int>();

                    foreach (var item in sumAsStr)
                    {
                        int num = int.Parse(item.ToString());
                        newList.Add(num);
                    }
                    int newSum = 0;
                    foreach (var item in newList)
                    {
                        newSum += item;
                    }

                    if (newSum <= 9)
                    {
                        sum = newSum;
                    }
                }
            }
            Console.WriteLine(sum);
        }
    }
}