08. Mentor Group

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

public class Soft
{
    public static void Main()
    {
        SortedDictionary<string,Student> group = new SortedDictionary<string,Student>();


        List<string> input = Console.ReadLine().Split(new char[] { ' ',','}).ToList();

        while(input[0]!="end")
        {
            if (input.Count == 1)
            {
                input = Console.ReadLine().Split(new char[] { ' ', ',' }).ToList();
                continue;

            }
            if (!group.ContainsKey(input[0]))
            {
                string name = input[0];
                input.RemoveAt(0);

                List<DateTime> dates = new List<DateTime>();
                //List<DateTime> attendance = input.Select(x => DateTime.ParseExact(input.ToString(),@"dd/MM/yyyy", CultureInfo.InvariantCulture)).ToList();
                foreach(var date in input)
                {
                    dates.Add(DateTime.ParseExact(date, @"dd/MM/yyyy", CultureInfo.InvariantCulture));
                }
                Student person = new Student();
                person.Name = name;
                person.Comments = new List<string>();
                person.Attendance = new List<DateTime>();
                person.Attendance.AddRange(dates);
                group.Add(name,person);
            }
            else
            {
                string name = input[0];
                input.RemoveAt(0);
                List<DateTime> dates = new List<DateTime>();
                foreach (var date in input)
                {
                    dates.Add(DateTime.ParseExact(date, @"dd/MM/yyyy", CultureInfo.InvariantCulture));
                }

                group[name].Attendance.AddRange(dates);
            }

            input = Console.ReadLine().Split(new char[] { ' ', ',' }).ToList();
        }

        input = Console.ReadLine().Split('-').ToList();
        while(input[0]!="end of comments")
        {

            if (!group.ContainsKey(input[0]))
            {
                input = Console.ReadLine().Split('-').ToList();
                continue;
            }
            else
            {

                string name = input[0];
                string comment = input[1];

                if(group.ContainsKey(name))
                {
                    Student student = group.Values.First(x => x.Name == name);
                    if(student.Comments==null)
                    student.Comments = new List<string>();
                    student.Comments.Add(comment);
                }

            }

            input = Console.ReadLine().Split('-').ToList();
        }

        foreach(var kvp in group.Values.GroupBy(x=>x.Name).OrderBy(x=>x.Key))
        {

            foreach(var kid in kvp)
            {
                Console.WriteLine(kid.Name);
                Console.WriteLine("Comments:");

                foreach(var notes in kid.Comments.Where(x=>x.Length>0))
                Console.WriteLine($"- {notes}");

                Console.WriteLine("Dates attended:");
                foreach (var days in kid.Attendance.OrderBy(x => x.Date))
                {
                    Console.WriteLine($"-- {days.ToString("dd/MM/yyyy")}");
                }

            }


        }
        Console.ReadLine();
    }
}

public class Student
{
    public string Name { get; set; }
    public List<string> Comments { get; set; }
    public List<DateTime> Attendance { get; set; }


}