pes

using System;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

namespace lab
{
    class Program
    {
        static bool hasDoubleNonVowel(string s)
        {
            char prev = '0';
            foreach (var c in s)
            {
                if ("aAoOuUiIeE".IndexOf(c) == -1)
                {
                    if (c == prev) return true;
                    prev = c;
                }
                else prev = '0';
            }
            return false;
        }

        static void Main(string[] args)
        {
            string text = File.ReadAllText(@"D://Projects//univ//sp//laba1//lab//lab//input.txt");
            text.Split(' ').Select(s => Regex.Replace(s, "[^0-9a-zA-Z]", "")) // Split and remove special symbols
                .Where(hasDoubleNonVowel) // Check 2 nonvowel
                .Distinct() // No duplicates
                .AsParallel().ForAll(s => Console.WriteLine(s)); // Output
            Console.ReadKey();
        }
    }
}