/// <summary>
        /// The mode of the set of lengths of lines in a string. Whatever
        /// number occurs the most as length of characters in a line is returned.
        /// </summary>
        /// <returns>The line length that occurs the most.</returns>
        /// <param name="input">Input.</param>
        private int LengthMode(string input)
        {
            string[] lines = input.Split('\n');
            var      modes = new System.Collections.Generic.Dictionary <int, int>();

            foreach (var line in lines)
            {
                if (modes.ContainsKey(line.Length))
                {
                    modes[line.Length] += 1;
                }
                else
                {
                    modes[line.Length] = 1;
                }
            }
            return(modes.Aggregate(modes.First(), (a, b) => {
                if (b.Value > a.Value)
                {
                    return b;
                }
                else
                {
                    return a;
                }
            }).Key);
        }