import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String t = in.next();

        int h = Integer.parseInt(t.substring(0,2));
        int m = Integer.parseInt(t.substring(3,5));

        if(m >= 55) {
            m = m + 5 - 60;
            if(h == 23)
                h = 0;
            else
                h++;
        } else {
            m += 5;
        }

        String ans = String.format("%02d:%02d", h, m);
        System.out.println(ans);
    }
}