SoftUni Courses

using System;
using System.Collections.Generic;

namespace CoursesSoftUni
{
    class Program
    {
        static void Main(string[] args)
        {
            string input;
            Dictionary<string, List<string>> courses = new Dictionary<string, List<string>>();
            while((input = Console.ReadLine()) != "end")
            {
                string[] inputArr = input.Split(" : ");
                if (courses.ContainsKey(inputArr[0]))
                {
                    courses[inputArr[0]].Add(inputArr[1]);
                }
                else
                {
                    courses.Add(inputArr[0], new List<string>());
                    courses[inputArr[0]].Add(inputArr[1]);
                }
            }

            foreach(var item in courses)
            {
                Console.WriteLine(item.Key + ": " + item.Value.Count);
                foreach(var participant in item.Value)
                {
                    Console.WriteLine("-- "+participant);
                }
            }
        }
    }
}