using System;

namespace DZ_ip
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            while (true)
            {
                Console.Write("Введите ip:");
                string ip = Console.ReadLine();
                if(NextIP(ip) == null)
                {
                    Console.WriteLine("Вы ввели неверный IP");
                    continue;
                }
                Return(NextIP(ip));
            }
        }

        static byte[] NextIP (string ip)
        {
            string[] ipArray = ip.Split('.');
            byte[] ipByte = new byte[ipArray.Length];
            for (int i = 0; i < ipArray.Length; i++)
            {
                if (Convert.ToInt32(ipArray[i]) > 255)
                {
                    ipByte = null;
                    break;
                }
                ipByte[i] = Convert.ToByte(ipArray[i]);
            }
            return ipByte;
        }

        static void Return (byte[] ip)
        {
            for (int i = ip.Length - 1; i >= 0; i--)
            {
                ip[i] += 1;
                if(ip[i] != 0)
                {
                    break;
                }
            }
            for (int i = 0; i < ip.Length; i++)
            {
                Console.Write(ip[i] + ".");
            }
            Console.WriteLine();
        }
    }
}