SumSeconds

import java.util.Scanner;

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

        int firstCompetitor = Integer.parseInt(scanner.nextLine());
        int secondCompetitor = Integer.parseInt(scanner.nextLine());
        int thirdCompetitor = Integer.parseInt(scanner.nextLine());

        int sumSeconds = firstCompetitor + secondCompetitor + thirdCompetitor;
        int minutes = sumSeconds / 60;
        int seconds = sumSeconds % 60;

        if (sumSeconds >= 0 && sumSeconds <= 59) {
            if (seconds <= 9) {
                System.out.println(minutes + ":" + "0" + seconds);
            } else {
                System.out.println(minutes + ":" + seconds);
            }
        } else if (sumSeconds >= 60 && sumSeconds <= 119) {
            if (seconds <= 9) {
                System.out.println(minutes + ":" + "0" + seconds);
            } else {
                System.out.println(minutes + ":" + seconds);
            }
        } else if (sumSeconds >= 120 && sumSeconds <= 179) {
            if (seconds <= 9) {
                System.out.println(minutes + ":" + "0" + seconds);
            } else {
                System.out.println(minutes + ":" + seconds);
            }
        }
    }
}