#include <stdio.h>
int main()
{
	int s,v;
	scanf("%d%d", &s, &v);
	int lim = 24 * 60;
	int time;
	if (s % v == 0)
	{
		time = s / v;
	}
	else {
		time = s / v + 1;
	}
	time = time + 10;
	if (time >= lim)
	{
		return 0;
	}
	if (time < 60)
	{
		int realtime = 60 - time;
		printf("\n");
		printf("07:");
		printf("%d", realtime);
	}
	if (time > 60)
	{
		int hour = time / 60;
		int time1 = time % 60;
		if (hour >= 8)
		{
			int realtime = 60- time1;
			int hour1 = hour - 8;
			printf("\n");
			printf("%d:", 24-hour1-1);
			printf("%d", realtime);

		}
		if (hour < 8)
		{
			int realhour = 8 - hour-1;
			int realtime = 60 - time1;
			printf("\n");
			printf("0%d:", realhour);
			if (realtime < 10)
			{

				printf("0%d", realtime);
			}
			if (realtime >= 10)
			{
				printf("%d", realtime);
			}
		}

	}

}