using System;

public class Program

{

    public static void Main()

    {

        var s1= int.Parse(Console.ReadLine());

        var s2= int.Parse(Console.ReadLine());

        var s3= int.Parse(Console.ReadLine());

        var secs= s1+s2+s3;

        var mins= 0 ;

        if (secs<=59 )

        {

            mins=0;

​

        }   

        if (secs>=60 && secs <=119)

        {

            mins=1 ;

            secs-=60;   

        }

        if (secs>=120 && secs<=179)

        {

            mins=2;

             secs-=120;

        }

        if (secs<10)

        {

            Console.WriteLine("{0}:0{1}", mins,secs);

        }

            else 

            {

            Console.WriteLine("{0}:{1}", mins,secs);

            }

    }

}