MultiverseCommunication

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

namespace _01.MultiverseCommunication
{
    class MultiverseCommunication
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            List<string> digits = ConvertStrToInt(input);
            Console.WriteLine(ConvertIndecimal(digits));
        }
        static string FindDigit(string substring)
        {
            string digit = String.Empty;
            switch (substring)
            {
                case "CHU": digit= "0"; break;
                case "TEL": digit= "1"; break;
                case "OFT": digit= "2"; break;
                case "IVA": digit= "3"; break;
                case "EMY": digit= "4"; break;
                case "VNB": digit= "5"; break;
                case "POQ": digit= "6"; break;
                case "ERI": digit= "7"; break;
                case "CAD": digit= "8"; break;
                case "K-A": digit= "9"; break;
                case "IIA": digit= "10"; break;
                case "YLO": digit= "11"; break;
                case "PLA": digit= "12"; break;
                default: break;
            }
            return digit;
        }

        static List<string> ConvertStrToInt(string input)
        {
            List<string> digits = new List<string>();

            for (int i = 0; i < input.Length; i+=3)
            {
                string substring = input.Substring(i, 3);
                digits.Add(FindDigit(substring));
            }

            return digits;
        }

        static BigInteger ConvertIndecimal(List<string> digits)
        {
            BigInteger result = 0;
            BigInteger powerOf13 = 1;
            for (int i = digits.Count- 1; i >= 0; i--)
            {
                result += powerOf13 * (BigInteger.Parse(digits[i].ToString()));
                powerOf13 *= 13;
            }
            return result;
        }

    }
}