#include<stdio.h>
int main()
{
	int s, v;
	scanf_s("%d %d", &s, &v);
	int t;
	t = (s + v - 1) / v + 10;
	int h, m;
	m =60- t % 60;
	if
		(t<=1440)
	{
		if (m != 60)
		{
			h = 7 - t / 60;
			printf("%2d:%2d", h, m);
		}
		else
		{
			h = 8 - t / 60;
			printf("%2d:00", h);
		}
	}
	return 0;
}