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

namespace ConsoleApplication55
{
    class Program
    {

        static void Main(string[] args)
        {
            string a = "14";
            int b = 13;
            int c = 8;
            try
            {
                if (b == 13)
                {
                    int temp = Convert.ToInt32(a, b);
                    Console.WriteLine(Convert.ToString(temp, c));
                }
                else
                {
                    Int64 temp = Convert.ToInt64(a, b);
                    Console.WriteLine(Convert.ToString(temp, c));
                }
            }
               catch(Exception)
            {
              Console.WriteLine("Некорректное значение параметра!");
            }

            Console.ReadLine();
        }
    }
}