using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Input
{
    class Program
    {
        static void Main(string[] args)
        {
            int step, word;
            string text, key, result = string.Empty;

            Console.Write("Enter Text : ");
            text = Console.ReadLine();
            Console.Write("Enter Key : ");
            key = Console.ReadLine();
            Console.Write("Enter Step : ");
            step = int.Parse(Console.ReadLine());

            // MIX STRING
            word = 0;

            if (step <= text.Length)
            {
                for (int i = 0; i < key.Length; i++)
                {
                    result += key.Substring(i, 1);
                    for (int k = 0; k < step; k++)
                    {
                        try
                        {
                            result += text.Substring(word, 1);
                            word++;
                        }
                        catch
                        {
                            break;
                        }
                    }
                }

                if (word < text.Length)
                {
                    result += text.Substring(word, (text.Length - word));
                }
            }

            Console.WriteLine("Result Text : " + result);

            // DECIPHER STRING

            Console.WriteLine("text: " + text);
            Console.WriteLine("key: " + key);

            Console.ReadKey();
        }
    }
}