01. Clock

using System;

namespace Clock
{
    class Program
    {
        static void Main(string[] args)
        {
            int h = 0;
            int m = 0;

            for (h = 0; h <= 23; h++)
            {
                for (m = 0; m <= 59; m++)
                {
                    Console.WriteLine($"{h}:{m}");
                }
            }
        }
    }
}