Sum seconds

using System;

class Program
{
    static void Main()
    {
        int sec1 = int.Parse(Console.ReadLine());
        int sec2 = int.Parse(Console.ReadLine());
        int sec3 = int.Parse(Console.ReadLine());
        int secs = sec1 + sec2 + sec3;
        int mins = (sec1 + sec2 + sec3) / 60;

        if (secs >= 0 && secs <= 59)
        {
            if (secs < 10)
            {
                Console.WriteLine("{0}:0{1}", mins, secs);
            }
            else
            {
                Console.WriteLine("{0}:{1}", mins, secs);
            }
        }
        else if (secs >= 60 && secs <= 119)
        {
            secs = secs - 60;
            if (secs < 10)
            {
                Console.WriteLine("{0}:0{1}", mins, secs);
            }
            else
            {
                Console.WriteLine("{0}:{1}", mins, secs);
            }
        }
        else if (secs >= 120 && secs <= 179)
        {
            secs = secs - 120;
            if (secs < 10)
            {
                Console.WriteLine("{0}:0{1}", mins, secs);
            }
            else
            {
                Console.WriteLine("{0}:{1}", mins, secs);
            }
        }
    }
}