FindPrimes

        public static string FindPrimes(int num)
        {
            string primesSt = "";
            int prime;
            while (num > 1)
            {
                prime = FindNextPrime(num);
                primesSt += prime.ToString() + " X ";
                num /= prime;
            }
            primesSt = primesSt.Remove(primesSt.LastIndexOf(" X "));
            return primesSt;
        }
        public static int FindNextPrime(int num)
        {
            for (int i = 2; i <= num; i++)
                if (num % i == 0)
                    return i;
            return 0;
        }
        static void Main(string[] args)
        {
            int num = int.Parse(Console.ReadLine());
            Console.WriteLine(num);
            Console.WriteLine("Primes string: {0}", FindPrimes(num));
        }