Time +15 Minutes

import java.util.Scanner;

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

        int hour = Integer.parseInt(scanner.nextLine());
        int min = Integer.parseInt(scanner.nextLine());

        min = min + 15;

        if (min > 59){
            min = min - 60;
            hour = hour + 1;
        }

        if (hour > 23){
            hour = 0;
        }

        if (min < 10) {
            System.out.printf("%d:0%d", hour, min);
        }else{
            System.out.printf("%d:%d", hour, min);
        }

    }
}