03. Take/Skip Rope

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

namespace TakeSkipRope
{
    class Program
    {
        static void Main(string[] args)
        {
            string message = Console.ReadLine();

            List<char> numberList = message.Where(x => x >= '0' && x <= '9').ToList();
            List<char> nonNumberList = message.Where(x => x < '0' || x > '9').ToList();
            int modificationIndex = 0;

            for (int i = 0; i < numberList.Count; i += 2)
            {
                modificationIndex += numberList[i] - 48;
                int finalIndex = modificationIndex + numberList[i + 1] - 48;
                finalIndex = finalIndex >= nonNumberList.Count ? nonNumberList.Count : finalIndex;

                for (int j = modificationIndex; j < finalIndex; j++)
                {
                    nonNumberList.RemoveAt(modificationIndex);
                }
            }
            while (modificationIndex < nonNumberList.Count)
            {
                nonNumberList.RemoveAt(modificationIndex);
            }
            Console.WriteLine(string.Join("", nonNumberList));
        }
    }
}