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

namespace ConsoleApplication30
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("input yor first split char: ");
            ConsoleKeyInfo usrKey1 = Console.ReadKey();
            Console.WriteLine("input yor second split char: ");
            ConsoleKeyInfo usrKey2 = Console.ReadKey();
            Console.WriteLine();

            Console.WriteLine("input your string: ");
            string str = Console.ReadLine();

            int firstIndex = str.IndexOf(usrKey1.KeyChar) - 1;
            int lastIndex = str.LastIndexOf(usrKey2.KeyChar);

            if (lastIndex == (-1) || firstIndex == (-1))
                Console.WriteLine("this chars is out of string");

            int count = lastIndex - firstIndex;

            Console.WriteLine(count);
            Console.ReadLine();
        }
    }
}