Integer insertion (char[] digits = command.ToCharArray()) -

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//You will receive a list of integers on the same line (separated by one space). On the next lines, you will start receiving a list of //strings, until you receive the string “end”. Your task is to insert each string (converted to integer) at a specific index in the //list. The index is determined by the first digit of the number.
//Example: 514  first digit – 5  insert 514 at the 5th index of the list.
//After you insert all the elements, print the list, separated by single spaces.

namespace integer_insertion
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> inputList = Console.ReadLine().Split(' ').Select(int.Parse).ToList();
            string command = string.Empty;
            bool end = true;
            while (end)
            {
                command = Console.ReadLine();
                if (command == "end")
                {
                    end = false;
                    break;
                }
                else
                {
                    int firstDigit = FirstDigit(command);
                    if (firstDigit <= inputList.Count)
                    {
                        inputList.Insert(firstDigit, int.Parse(command));
                    }
                    else
                    {
                        inputList.Add(int.Parse(command));
                    }

                }
            }
            Console.WriteLine(string.Join(" ", inputList));
        }
        static int FirstDigit(string command)
        {
            char[] digits = command.ToCharArray();
            int firstDigit = (int) digits[0] - 48;
            return firstDigit;
        }
    }
}