Second

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Globalization;

namespace _1000DaysAfterBirth
{
    class Program
    {
        static void Main()
        {
            int firstSeconds = int.Parse(Console.ReadLine());
            int secondSeconds = int.Parse(Console.ReadLine());
            int thirdSeconds = int.Parse(Console.ReadLine());

            TimeSpan timeSpanFromSeconds = TimeSpan.FromSeconds(firstSeconds + secondSeconds + thirdSeconds);

            Console.WriteLine($"{timeSpanFromSeconds.Minutes}:{timeSpanFromSeconds.Seconds:d2}");
        }
    }
}