internal static Stack<string> CreateStack(string input) { var lines = input.Trim().Split(' '); var stack = new Stack<string>(); // LIFO for (var i = (lines.Length - 1); i >= 0; i--) { var line = lines[i]; if (!string.IsNullOrEmpty(line)) { line = line.Trim(); stack.Push(line); } } return stack; }