<RuntimeDirectory>\System.configuration.dll <RuntimeDirectory>\System.Security.dll System.Configuration var input = File.ReadAllLines(Path.Combine(Path.GetDirectoryName(Util.CurrentQueryPath), "..", "day1.txt")).Select(int.Parse).ToList(); var part1 = input.Sum(); part1.Dump(); var frequencies = new List(); var frequency = 0; var part2 = 0; while (part2 == 0){ foreach (var change in input){ frequency += change; if (frequencies.Contains(frequency)){ part2 = frequency; break; } frequencies.Add(frequency); } } part2.Dump();