import java.util.Scanner;
public class Main {
    public static void main(String args[]) {
        Scanner scanner = new Scanner(System.in);
        float s = scanner.nextFloat();
        float v = scanner.nextFloat();
        double t = (s / v) + 10;
        int m = (int) (60 - t);
        int h = 7;
        if (m < 0) {
            m = m * (-1);
            int i = 0;
            i = (m / 60) + 1;
            h = h - i;
            m = 60 - (m % 60);
            if (h < 0) {
                h = 24 + (h);
            }
        }
        System.out.printf("%02d" + ":" + "%02d", h, m);
    }
}