Sum Seconds

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

namespace ConsoleApp9
{
    class Program
    {
        static void Main(string[] args)
        {
            int racer1 = int.Parse(
                Console.ReadLine());
            int racer2 = int.Parse(
                Console.ReadLine());
            int racer3 = int.Parse(
                Console.ReadLine());

            int sum = (racer1 + racer2 + racer3);
            int minutes = sum / 60;
            int seconds = sum % 60;

            Console.WriteLine("{0}:{1:00}", minutes , seconds);
        }
    }
}