#include<stdio.h>
int main(void)
{
	int s, v,time,sum_time,time_,a=0;
	scanf("%d %d", &s, &v);
	if (s % v == 0)
	{
		time = s / v + 10;
	}
	else
	{
		time = s / v + 10 + 1;
	}
	sum_time = 6 * 80 + 24 * 60;
	if (sum_time - time >= 24 * 60)
	{
		time_ = sum_time - time - 24 * 60;
	}
	else
	{
		time_ = sum_time - time;
	}
	while (time_ >= 60)
	{
		time_ -= 60;
		a++;
	}
	if (a < 10)
	{
		printf("0%d:%d", a, time_);
	}
	else
	{
		printf("%d:%d", a, time_);
	}
	return 0;
}