#include <cstdio>
#include<math.h>
int main()
{
	int s, v, a, b,c,d;
    scanf_s("%d%d", &s, &v);
	a =ceil( s / v / 60.0);
	b = ceil((double)s / v)+10;
	d = 60 - b;
	c = 8 - a;
	if (c < 0)
	{
		c = 8 - a + 24;
	}
    printf("%02d:%02d", c, d);
}