NMS

using System;
using System.Text;

class Program
{
    static void Main()
    {
        string input;
        var sb = new StringBuilder();

        while ((input = Console.ReadLine()) != "---NMS SEND---")
        {
            sb.Append(input);
        }

        var resultSB = new StringBuilder();
        var delimeter = Console.ReadLine();

        for (int i = 0; i < sb.Length  ; i++)
        {
            var currentChar = Char.ToLower(sb[i]);
            if (i != sb.Length-1)
            {
                if (currentChar <= Char.ToLower(sb[i + 1]))
                {
                    resultSB.Append(sb[i]);
                }
                else
                {
                    resultSB.Append(sb[i]);
                    resultSB.Append(delimeter);
                }
            }
            else
            {
                resultSB.Append(sb[i]);
                break;
            }
        }
        Console.WriteLine(resultSB);
    }
}