using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            var regexTelephone = new Regex(@"^(0[0-9]{2,3}\-)?([2-9][0-9]{6,7})+(\-[0-9]{1,4})?$");
            var regexMobilePhone = new Regex(@"^[1][358]\d{9}$");
            while (true)
            {
                Console.Write("Phone:");
                var inputString = Console.ReadLine();
                if (string.IsNullOrWhiteSpace(inputString)) continue;
                if (regexTelephone.IsMatch(inputString) || regexMobilePhone.IsMatch(inputString))
                {
                    Console.WriteLine("Okay!");
                    break;
                }
                Console.WriteLine("Wrong!");
            }
            Console.Write("Press any key to exit...");
            Console.ReadKey();
        }
    }
}