int main() {
	int s, v, a, b, c, t;


	scanf("%d%d", &s, &v);

		if (s % v == 0) {
			t = s / v;
		} else {
			t = s / v + 1;
		}


		a = (470 - t) / 60;



		if (t <= 470) {
			c = a;
			b = 470 - t - a * 60;
		} else {
			c = 24 + a;
			b = 470 - t - c * 60 + 8 * 24;
		}

		printf("%02d:%02d", c, b);
	

	return 0;
}```