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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string s, x, a, b;
            Console.Write("Enter s string: ");
            s = Console.ReadLine();

            Console.Write("Enter s string: ");
            x = Console.ReadLine();

            Console.Write("Enter a string: ");
            a = Console.ReadLine();

            Console.Write("Enter b string: ");
            b = Console.ReadLine();

            Console.WriteLine();

            Console.WriteLine(chekIfX_ExistInS(s, x, a, b));
        }


        private static string chekIfX_ExistInS(string str, string searchedStr, string a, string b)
        {
            if (str.Contains(searchedStr) && str.Contains(a) && str.Contains(b))
            {
                return "Substring \"" + searchedStr + "\" exist in string \"" + str + "\" with start index " +
                    str.IndexOf(searchedStr) + ".";
            }

            return "Substring \"" + searchedStr + "\" does not exist in string \"" + str + "\"";
        }
    }
}