import java.util.Scanner;

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

        int firstCompetition = scanner.nextInt();
        int secondCompetition = scanner.nextInt();
        int thirdCompetition = scanner.nextInt();

        int secondInputs = firstCompetition + secondCompetition + thirdCompetition;

        double minutes = Math.round((secondInputs / 60d) * 100d) / 100d;
        double decimals = Math.round((minutes - Math.floor(minutes)) * 100d) / 100d ;
        int seconds =  (int)Math.round(decimals * 60);

        if (seconds < 10){
            System.out.println((int) minutes + ":0" + seconds);
        } else if (seconds == 0){
            System.out.println((int) minutes + ":00");
        } else if (seconds == 10 & seconds == 20 & seconds == 30 & seconds == 40 & seconds == 50){
            System.out.println((int) minutes + ":" + seconds + "0");
        } else {
            System.out.println((int) minutes + ":" + seconds);
        }


    }
}