#include<math.h>
#include<stdio.h>
int main()
{
	double s,v,t,z;
	int i,j,x,y,m;
	scanf("%lf %lf",&s,&v);
	t = s / v;
	j = (int)round(t);
	if(t > j)
	j++ ; 
	z = j + 10;
	t = z / 60.0;
	i = (int)t;
	m = (int)z;
	x = m % 60;
	if(j >= 470 )
	{
		y = 8 + 24 - i - 1;
	}
	else y = 8 - i - 1;
	
	if(x == 0)
	{
		y++;
	}
	else if(x != 60)
	x = 60  - x;


	if(y > 10 && x > 10)
		printf("%d:%d",y,x);
	else  if(y > 10 && x < 10)
			printf("%d:0%d",y,x);
			else  if(y < 10 && x > 10)
					printf("0%d:%d",y,x);
					else printf("0%d:0%d",y,x);
	return 0;
}