else if (command == "Exercise")
                {

                    if (lessons.Contains(condition) && !lessons.Contains(condition + "-Exercise"))
                    {
                        int index = lessons.IndexOf(condition);
                        lessons.Insert(index + 1, condition + "-Exercise");

                    }
                    else if(!lessons.Contains(condition))
                    {
                        lessons.Add(condition);
                        lessons.Add(condition + "-Exercise");
                    }
                }