import java.util.Scanner;

public class time15 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

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

        if (min>=46&& min<=54){
            hour += 1;
            min = (min+15)-60;
            if (hour==24){
                hour = 0;
            }
            System.out.printf("%d:0%d",hour,min);
        } else if (min<=44) {
            min = (min + 15);
            System.out.printf("%d:%d", hour, min);
        } else if (min==45) {
            hour += 1;
            min = (min + 15)-60;
            if (hour==24){
                hour = 0;
            }
            System.out.printf("%d:%d0", hour, min);
        } else if (min>=55){
            hour += 1;
            min = (min+15)-60;
            if (hour==24){
                hour = 0;
            }
            System.out.printf("%d:%d", hour, min);
        }


    }
}