int main() {
	int s, v;
	scanf("%d %d", &s, &v);
	
	int min = s / v; 
	if (s % v != 0) min += 1;
 
	int hour;
	hour = min / 60;
	int leftmin = min - hour * 60;
	int hour1=8-hour; //显示小时

	int min1 = 60 - leftmin; //显示分钟
	if (leftmin > 0) hour1 -= 1;
	if (hour1 < 0) hour1 += 24;
	if (hour1 < 10 && hour1>0) {
		printf("0"); printf("%d",hour1);
	}
	else if (hour1 >= 10)printf("%d", hour1);
	else if (hour1 == 0) printf("00");
	printf(":");
	if (min1 < 10 && min1>0) {
		printf("0%d", min1);

	}
	else if (min1 == 0) printf("00");
	else printf("%d", min1);

	return 0;
}