using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Courses
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] input = Console.ReadLine().Split(" : ");
            Dictionary<string, List<string>> dictOfStudents = new Dictionary<string, List<string>>();

            while (input[0] != "end")
            {
                string courseName = input[0];
                string studentName = input[1];

                AddCourseOrStudent(dictOfStudents, courseName, studentName);

                input = Console.ReadLine().Split(" : ");
            }

            foreach (var item in dictOfStudents.OrderByDescending(x => x.Value.Count))
            {
                Console.WriteLine($"{item.Key}: {item.Value.Count}");
                foreach (var name in dictOfStudents[item.Key].OrderBy(x => x))
                {
                    Console.WriteLine("-- " + name);
                }
            }


        }

        static Dictionary<string, List<string>> AddCourseOrStudent(Dictionary<string, List<string>> dict, string course, string student)
        {
            if (dict.ContainsKey(course))
            {
                dict[course].Add(student);
            }
            else
            {
                dict.Add(course, new List<string>() { student });
            }

            return dict;
        }
    }
}