import java.util.Scanner;

public class SumSeconds {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int sec1 = Integer.parseInt(scanner.nextLine());
        int sec2 = Integer.parseInt(scanner.nextLine());
        int sec3 = Integer.parseInt(scanner.nextLine());

        int seconds = sec1 + sec2 + sec3;
        int mins = 0;

        if (seconds > 119){
            seconds -= 120;
            mins = 2;
        }else if (seconds > 59){
            seconds -= 60;
            mins = 1;
        }

        String secondsString = "";
        if(seconds < 10){
            secondsString = "0";
        }
        secondsString += Integer.toString(seconds);

        System.out.printf(mins + ":" + secondsString);
    }
}