private static Dictionary<string, string> GetNGramms(List<List<string>> text, int n)
        {
            var result = new Dictionary<string, Dictionary<string, int>>();
            foreach (var sentence in text)
                for (var wordIterator = 0; wordIterator < sentence.Count - n + 1; wordIterator++)
                {
                    var key = "";
                    for (var keyIterator = wordIterator; keyIterator < wordIterator + n - 1; keyIterator++)
                    {
                        key += sentence[keyIterator];
                        if (keyIterator != wordIterator + n - 1)
                            key += " ";
                    }

                    key = key.Substring(0, key.Length - 1);

                    if (!result.ContainsKey(key))
                        result[key] = new Dictionary<string, int>();
                    if (!result[key].ContainsKey(sentence[wordIterator + n - 1]))
                        result[key][sentence[wordIterator + n - 1]] = 0;
                    result[key][sentence[wordIterator + n - 1]] += 1;
                }

            return GetFinalNGrammsListWithoutFrequncy(result);
        }