static string CalculateCheapestMonth(ListNodes<Residents> residentsListNodes, ListNodes<Utilities> utilitiesListNodes)
        {
            var cheapestMonth = new Dictionary<string, Dictionary<string, double>>();
            var cheapestMonthListNodes = new ListNodes<CheapestMonth>();
            var temp = residentsListNodes;
            for (residentsListNodes.StartingNode(); residentsListNodes.Contains(); residentsListNodes.RightNode())
            {
                if (cheapestMonth.ContainsKey(residentsListNodes.GetData().Month))
                {
                    if (cheapestMonth[residentsListNodes.GetData().Month].ContainsKey(residentsListNodes.GetData().UtilityCode))
                    {

                        cheapestMonth[residentsListNodes.GetData().Month][residentsListNodes.GetData().UtilityCode] +=
                            FindUtilityPrice(utilitiesListNodes, residentsListNodes.GetData().UtilityCode) * residentsListNodes.GetData().ServiceCount;
                    }
                    else
                    {
                        cheapestMonth[residentsListNodes.GetData().Month].Add(
                       residentsListNodes.GetData().UtilityCode,
                       FindUtilityPrice(utilitiesListNodes, residentsListNodes.GetData().UtilityCode) * residentsListNodes.GetData().ServiceCount
                       );
                    }
                }
                else
                {
                    cheapestMonth.Add(residentsListNodes.GetData().Month, new Dictionary<string, double>());
                    cheapestMonth[residentsListNodes.GetData().Month].Add(
                        residentsListNodes.GetData().UtilityCode,
                        FindUtilityPrice(utilitiesListNodes, residentsListNodes.GetData().UtilityCode) * residentsListNodes.GetData().ServiceCount
                        );
                }
            }

            foreach (KeyValuePair<string, Dictionary<string, double>> item in cheapestMonth)
            {
                foreach (KeyValuePair<string, double> utility in cheapestMonth[item.Key])
                {
                    cheapestMonthListNodes.AddData(new CheapestMonth(item.Key, utility.Key, utility.Value));
                }
            }

            var cheapestMonthUtility = cheapestMonthListNodes.OrderBy(x => x.Price).FirstOrDefault();

            for (utilitiesListNodes.StartingNode(); utilitiesListNodes.Contains(); utilitiesListNodes.RightNode())
            {
                if (cheapestMonthUtility.UtilityCode == utilitiesListNodes.GetData().ServiceCode)
                {
                    cheapestMonthUtility.UtilityCode = utilitiesListNodes.GetData().ServiceName;
                }
            }
            if (cheapestMonthUtility != null)
            {
                return $"{cheapestMonthUtility.Month} mėnesį {cheapestMonthUtility.UtilityCode} kainavo pigiausiai";
            }
            return "Nerasta";
        }